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78 Evolution News Articles
for October 2017
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10-19-17 The mass extinction that might never have happened
The mass extinction that might never have happened
An ecological catastrophe 201 million years ago supposedly paved the way for the rise of giant dinosaurs, but it may not have happened that way after all. Should the “big five” really be the “big four”? For decades, we have recognised five devastating mass extinctions that punctuate the last half-billion years of evolution. But now two geologists are controversially arguing that the end-Triassic extinction – often described as the third largest – has no place on that list. “Certainly there was an environmental crisis, but it’s not a mass extinction per se,” says Lawrence Tanner at Le Moyne College at Syracuse, New York. “It’s misleading to continue to call it one.” If he is correct, our understanding of the early evolution of dinosaurs will need rewriting. The end-Triassic extinction of 201 million years ago is less famous than those before and after. The end-Permian “mother of all mass extinctions” 252 million years ago nearly obliterated all complex life, while the extinction at the close of the Cretaceous 66 million years ago is famous because it wiped out all dinosaurs, apart from birds. The end-Triassic extinction has been linked to a spate of volcanic eruptions around the birth of the central Atlantic Ocean. This “central Atlantic magmatic province” (CAMP) released carbon dioxide and sulphurous compounds into the atmosphere – supposedly triggering global warming, acid rain and widespread extinctions on land and at sea.

10-18-17 This ancient clock rules our lives — and determines our health
This ancient clock rules our lives — and determines our health
Our lives are ruled by time; we use time to tell us what to do. But the alarm clock that wakes us in the morning or the wristwatch that tells us we are late for supper are unnatural clocks. Our biology answers to a profoundly more ancient beat that probably started to tick early in the evolution of all life. Embedded within the genes of us, and almost all life on Earth, are the instructions for a biological clock that marks the passage of around 24 hours. Biological clocks or "circadian clocks" help time our sleep patterns, alertness, mood, physical strength, blood pressure, and much more. Under normal conditions, we experience a 24-hour pattern of light and dark, and our circadian clock uses this signal to align biological time to the day and night. The clock is then used to anticipate the differing demands of the 24-hour day and fine-tune physiology and behavior in advance of the changing conditions. Body temperature drops, blood pressure decreases, cognitive performance drops, and tiredness increases in anticipation of going to bed. While before dawn, metabolism is geared-up in anticipation of increased activity when we wake. A circadian clock also stops everything happening at the same time, ensuring that biological processes occur in the appropriate sequence. For cells to work properly they need the right materials in the right place at the right time. Thousands of genes have to be switched on and off in order and in harmony. Proteins, enzymes, fats, carbohydrates, hormones, nucleic acids, and other compounds have to be absorbed, broken down, metabolized, and produced in a precise time window. Energy has to be obtained and then allocated to growth, reproduction, metabolism, locomotion, and cellular repair.

10-18-17 Hunger-blocking injection lets fat monkeys quickly lose weight
Hunger-blocking injection lets fat monkeys quickly lose weight
A protein injection that decreases appetite has been found to help obese monkeys slim down fast, and to cut their risk of developing diabetes. A protein injection that decreases appetite helps obese monkeys to slim down fast and cuts their risk of diabetes. Excitement is growing about a protein called GDF15, which naturally regulates body weight in humans and animals. When extra amounts are injected into mice, they eat less, lose weight and have fewer signs of diabetes. Several research teams have tried developing GDF15 as an obesity treatment, but it breaks down too quickly in the bloodstream to work. Now a team led by Murielle Véniant at pharmaceutical company Amgen has found a way to make GDF15 last longer in the body. The team added an antibody fragment onto GDF15. Antibodies are immune proteins that help recognise foreign molecules in the body. They found that this hybrid protein caused obese monkeys to eat about 40 per cent less. When given weekly injections, the monkeys lost 10 per cent of their body weight over 6 weeks. Their glucose tolerance also improved, making them less likely to develop type 2 diabetes.

10-18-17 Getting on cancer’s nerves: A surprising way to thwart tumours
Getting on cancer’s nerves: A surprising way to thwart tumours
A technique for alleviating pain has exposed cancer's weak spot and may finally enable us to stop the disease by disabling the nerves that help it spread. DAVID MARTINEZ lives with excruciating pain. He has pancreatitis, a condition in which the pancreas becomes severely inflamed. Over the past five months, he has received three injections of a local anaesthetic into nerves in his abdomen to help ease the agony. But eventually the medicine wears off, and the pain returns. As if pancreatitis weren’t bad enough, Martinez, a 41-year-old former forklift operator in Pasco, Washington, has something else to worry about. Chronic inflammation of the pancreas is a major risk factor for cancer. “I’m afraid of it happening,” he says. But what if the painkilling injections Martinez is getting could do more than just ease his discomfort – even help ward off cancer altogether? New evidence is causing a rethink of the way cancer invades our bodies. It now seems that targeting nerve cells might be an effective way to fight tumours – and even prevent them developing in the first place. Some even think that focussing on nerves may be the missing piece in the fight against the disease. As Gustavo Ayala at the University of Texas Health Science Center at Houston sees it, “If you don’t take care of the nerves, you’re not going to cure cancer.”

10-18-17 A common herbal medicine may cause liver cancer mutations
A common herbal medicine may cause liver cancer mutations
A compound found in some plants used in traditional medicine has been linked to a 78 per cent of cases of liver cancer in hospitals in Taiwan. A commonly-used herbal medicine causes mutations that are linked to liver cancer, according to research in Taiwan. Extracts taken from plants of the genus Aristolochia, which are used in traditional Chinese medicine to treat a wide range of conditions, may be responsible for many liver cancers in Asia. There are over 500 species of Aristolochia, around 100 of which have been used in herbal medicines. “They have very beautiful, trumpet-shaped flowers,” says Steven Rozen at Duke-NUS Medical School in Singapore. This has led to them being given names like “Dutchman’s pipe”. Extracts of the plants – taken from the flowers, root or stem, for example – have long been used in herbal medicine. But fears over their safety were raised in the 1990s, when women who were given trial weight loss drugs containing Aristolochia extracts developed kidney failure. Since then, the plant extracts have also been linked to Balkan nephropathy – a kidney disease affecting people in Bosnia, Bulgaria, Croatia, Romania and Serbia. In 2013, researchers found that a compound in the plants, known as aristolochic acid, seems to cause gene mutations by targeting the base adenine, a component of DNA’s genetic code. “It attacks any part of the genome with equal opportunity,” says Rozen.

10-18-17 The science behind why sweet and salty foods taste so good together
The science behind why sweet and salty foods taste so good together
Go ahead and keep dipping those fries into your milkshake. Sweet and salty: They're two things that go together like Jacques and Julia, the Queen and her martini, and (literally) peanut butter and jelly. And though they're polar opposites on the flavor spectrum, that hasn't stopped us from putting the word salted in front of every trending dessert or dipping french fries into a chocolate Frosty. Here's why this beloved combination works so well — and, more importantly, why people who put pineapple on pizza actually are onto something. Salt makes things taste better, not saltier. Scientifically, you have your taste buds to thank for this. A study published in the journal Proceedings of the National Academy of Sciences suggests that in addition to being able to sense sweet and salty, our tongues have additional sweetness receptors that activate only when sugar is in the presence of salt. So as contradictory as it seems, even just a sprinkle of salt on a watermelon wedge can make the fruit taste even sweeter. Our bodies naturally crave both salt and sugar. We're hardwired to crave junk food (which, surprise, tends to be loaded with salt and sugar). According to Barb Stuckey, the author of TASTE: Surprising Stories and Science About Why Food Tastes Good, we've evolved to gravitate to sweet foods since they're traditionally the most energy rich (read: high in calories). Our bodies are also conditioned to like salty foods since sodium is an essential mineral we need to function.

10-18-17 Moms tweak the timbre of their voice when talking to their babies
Moms tweak the timbre of their voice when talking to their babies
Mothers shift the timbre, or quality, of their voice when talking to their babies, a new study finds. Voices carry so much information. Joy and anger, desires, comfort, vocabulary lessons. As babies learn about their world, the voice of their mother is a particularly powerful tool. One way mothers wield that tool is by speaking in the often ridiculous, occasionally condescending baby talk. Also called “motherese,” this is a high-pitched, exaggerated language full of short, slow phrases and big vocal swoops. And when confronted with a tiny human, pretty much everybody — not just mothers, fathers and grandparents — instinctively does it. Now, a study has turned up another way mothers modulate their voice during baby talk. Instead of focusing on changes such as pitch and rhythm, the researchers focused on timbre, the “color” or quality of a sound. Timbre is a little bit nebulous, kind of a “know it when you hear it” sort of thing. For instance, the timbre of a reedy clarinet differs from a bombastic trumpet, even when both instruments are hitting the same note. The same is true for voices: When you hear the song “Hurt,” you don’t need to check whether it’s Nine Inch Nails’ Trent Reznor or Johnny Cash singing it. The vocal fingerprints make it obvious.

10-17-17 Four brain genes help explain obsessive compulsive disorder
Four brain genes help explain obsessive compulsive disorder
OCD has been linked to genes active in a brain circuit involved in learning and decisions. The finding may help explain why the condition can run in families. Four genes have been identified that are linked to obsessive compulsive disorder (OCD). The genes all play a role in the same brain circuit, and may help explain why people are more likely to have OCD if they have a relative with the condition. People with OCD have intrusive thoughts and feel driven to repeat rituals, such as handwashing, to relieve their anxiety. To investigate if OCD has a genetic basis, Hyun Ji Noh at the Broad Institute of MIT and Harvard and her colleagues compared more than 600 genes across 592 people with OCD, and 560 people who don’t have it. They chose these candidate genes from several lines of evidence. Of these genes, 222 had been linked to compulsive grooming in mice, and 196 had been linked to autism in people – a condition that can involve repetitive behaviours. The team also looked at 56 genes that they had identified in a study of dogs with canine compulsive disorder, a condition in which dogs repeatedly chase their tails, pace back and forth, groom themselves or sucks things, sometimes for hours at a time. The analysis identified four genes that are different in people who have OCD. All four of these are active in a brain circuit that links the striatum, thalamus and cortex regions.

10-17-17 How volcanoes may have ended the dynasty of Ptolemy and Cleopatra
How volcanoes may have ended the dynasty of Ptolemy and Cleopatra
Volcanic ash layers suggest eruptions may have messed with crop-dependent monsoons, leading to an era of revolt. An Italian volcano erupted in 44 B.C., likely reducing monsoon rains that fed into the Nile River and ultimately fueling civic unrest in Ptolemaic Egypt. A series of volcanic eruptions may have helped bring about the downfall of the last Egyptian dynasty 2,000 years ago. By suppressing the monsoons that swelled the Nile River each summer, triggering flooding that supported the region’s agriculture, the eruptions probably helped usher in an era of periodic revolts, researchers report online October 17 in Nature Communications. That upheaval ultimately doomed the dynasty that ruled Egypt’s Ptolemaic Kingdom for nearly 300 years until the death of Cleopatra. To piece together this puzzle, Yale University historian Joseph Manning and his colleagues first compared records of Nile River heights dating back to A.D. 622 with volcanic eruptions recorded in ice cores from Greenland and Antarctica that date back 2,500 years. Ash layers in the ice cores, corresponding to “eruption years”, were linked to years of less extensive flooding, they found.

10-17-17 A universal flu vaccine may be nearing reality
A universal flu vaccine may be nearing reality
New strategies aim to attack the influenza virus in creative ways. The flu kills tens of thousands of people in the United States each year, and protection is made harder by the need for an annual shot. A onetime vaccine is getting closer to reality. One of the planet’s deadliest viruses makes an annual pass through the United States with little fanfare. It rarely generates flashy headlines or news footage of health workers in hazmat suits. There’s no sudden panic when a sick person shows up coughing and feverish in an emergency room. Yet before next spring, this season’s lethal germ will probably have infected millions of Americans, killing tens of thousands. Still, it’s often referred to as just the flu. The influenza virus seems so normal to most Americans that only about half of us will heed those “time for your flu shot” banners that pop up at pharmacies and worksites every autumn. Those annual shots remain the best means of protection, but they must be manufactured months before flu season starts, based on a best educated guess of what strains of the virus will be circulating. That means even in a successful year, vaccine performance may not be impressive. During the 2015–2016 season, only about half of those immunized were protected, according to a study in the Aug. 10 New England Journal of Medicine. Some years’ vaccines are duds: For the 2014–2015 season, the vaccine protected only 19 percent of people who received it, based on U.S. Centers for Disease Control and Prevention data.

10-16-17 Gut fungi might be linked to obesity and inflammatory bowel disorders
Gut fungi might be linked to obesity and inflammatory bowel disorders
Yeast and bacteria can team up to cause trouble. Candida tropicalis usually grows as a harmless roundish budding yeast, but in the presence of two bacteria it stretches into long filaments that may provoke inflammation in intestines. Fungi may affect gut health in unexpected ways, new research suggests. High-fat diets may alter relationships between bacteria and fungi in mice’s intestines, contributing to obesity, researchers report October 11 in mSphere. In independent work, researchers report that a fungus teams up with two types of bacteria to fuel gut inflammation in people with Crohn’s disease. That work was summarized October 4 in Digestive and Liver Disease. Together, the studies are part of a growing body of research indicating that relationships between the bacterial and fungal kingdoms can affect health, says David Andes, a fungal biologist at the University of Wisconsin School of Medicine and Public Health in Madison. Andes wasn’t involved in either study. Scientists have already described links between health issues, including obesity, and gut bacteria — often called the microbiome. But far less is known about the role of the gut’s fungal mix, or mycobiome.

10-16-17 To understand the origins of pain, ask a flatworm
To understand the origins of pain, ask a flatworm
Experiments in planarians identify a chemical middleman that triggers the body’s ouch detectors. In planarians, a protein called TRPA1 detects hydrogen peroxide, a molecule produced when cells are damaged. These new results give hints about the evolution of human pain. Hydrogen peroxide, a molecule produced by cells under duress, may be a common danger signal, helping to alert animals to potential harm and send them scurrying. New details from planarian flatworms of how this process works may deepen scientists’ understanding of how people detect pain, and may ultimately point to better ways to curb it. “Being able to get a big-picture view of how these systems are built and what they’re cuing in on is always really helpful,” says biologist Paul Garrity of Brandeis University in Waltham, Mass. And by finding cellular similarities among planarians, fruit flies and people, the new study, published online October 16 in Nature Neuroscience, provides hints about how this threat-detecting system might have operated hundreds of millions of years ago.

10-14-17 Magic mushrooms can 'reset' depressed brain
Magic mushrooms can 'reset' depressed brain
A hallucinogen found in magic mushrooms can "reset" the brains of people with untreatable depression, raising hopes of a future treatment, scans suggest. The small study gave 19 patients a single dose of the psychedelic ingredient psilocybin. Half of patients ceased to be depressed and experienced changes in their brain activity that lasted about five weeks. However, the team at Imperial College London says people should not self-medicate. There has been a series of small studies suggesting psilocybin could have a role in depression by acting as a "lubricant for the mind" that allows people to escape a cycle of depressive symptoms. But the precise impact it might be having on brain activity was not known. The team at Imperial performed fMRI brain scans before treatment with psilocybin and then the day after (when the patients were "sober" again). The study, published in the journal Scientific Reports, showed psilocybin affected two key areas of the brain.

  • The amygdala - which is heavily involved in how we process emotions such as fear and anxiety - became less active. The greater the reduction, the greater the improvement in reported symptoms.
  • The default-mode network - a collaboration of different brain regions - became more stable after taking psilocybin.

10-13-17 Magic mushroom extract changes brains of people with depression
Magic mushroom extract changes brains of people with depression
Psilocybin, a hallucinogenic compound found in magic mushrooms, may help re-set the activity of neural circuits in the brain that are involved in depression. Psilocybin, a hallucinogenic compound found in magic mushrooms, may help re-set the activity of neural circuits in the brain that are involved in depression. Magic mushroom enthusiasts have long believed that the drug’s ability to induce profound-feeling experiences could be therapeutically useful. Brain-imaging studies have shown that psilocybin targets areas of the brain overactive in depression. Last year, Robin Carhart-Harris of Imperial College London and his colleagues conducted the first clinical trial of using psilocybin to treat depression, and got some encouraging results. The trial only involved 12 people and no control group, but the team found that after two sessions of psilocybin-assisted psychotherapy, all of the volunteers had reduced symptoms. Now Carhart-Harris and his team have shown that psilocybin seems to cause changes in the brains of people with depression. The study involved 19 people who, like in the previous study, had depression that had not been helped by conventional treatments.

10-13-17 Sperm age calculator tells men how decrepit their sperm are
Sperm age calculator tells men how decrepit their sperm are
An epigenetic calculator can assess a man’s sperm, guessing how old he is, and revealing how badly smoking may have damaged his gonads. A sperm age calculator can tell men how “old” their sperm are, using clues from DNA analysis, and has revealed some of the effects of smoking on sperm. While a woman’s age has long been known to affect the health of her offspring, we have only recently begun to understand how a father’s age can have similar effects. Older fathers are now known to pass on more genetic mutations to their children than older mothers do. And children of older fathers are more likely to have autism and schizophrenia. “The hope is that we could potentially screen people and say, ‘your sperm is really old’, and identify risks for the offspring,” says Tim Jenkins at the University of Utah. Growing evidence suggests that older dads might pass on health risks through epigenetic tags on the DNA in their sperm. These tags alter how active genes are, and lifestyle factors such as diet and smoking are known to make epigenetic changes that may affect the next generation. Ageing is also a factor. Jenkins and his colleagues have studied the sperm of 350 men, looking for these genetic switches. So far, the team have found changes at 147 points in the genome that seem to be linked to a man’s age.

10-13-17 DNA study provides insight into how to live longer
DNA study provides insight into how to live longer
Every year spent in education adds an average of 11 months to people's lifespan, say scientists. The researchers say a person loses two months for every kilogram overweight they are - and seven years for smoking a packet of cigarettes a day. Unusually, the Edinburgh university team found their answers by analysing differences in people's genetic code or DNA. Ultimately they think it will reveal new ways of helping us to live longer. The group used the genetic code of more than 600,000 people who are taking part in a natural, yet massive, experiment. If someone smokes, drinks, dropped out of school and is overweight, it can be difficult to identify the impact of one specific unhealthy behaviour. Instead, the researchers turned to the natural experiment. Some people carry mutations in their DNA that increase appetite or make them more likely to put on weight, so researchers were able to compare those programmed to eat more with those who were not - irrespective of their wider lifestyles. Dr Peter Joshi, from the university's Usher Institute, said: "It doesn't mess up the analysis. You can look directly at the effect of weight, in isolation, on lifespan." Similar sets of mutations have been linked to how long people spend in education and the enjoyment they get from smoking or drinking.The research team also found specific mutations in human DNA that alter lifespan, reported in the journal Nature Communications.

  • Mutations in a gene (a set of instructions in DNA) that is involved in running the immune system could add seven months of life on average
  • People with a mutation that increased levels of bad cholesterol knocked eight months off life expectancy
  • A rare mutation in a gene - APOE - linked to dementia reduced lifespans by 11 months
  • And one that made smoking more appealing cut lives by five months

10-13-17 Unlocking the body clock
Unlocking the body clock
Three American scientists have won the Nobel Prize in physiology or medicine for their work on circadian rhythms, the internal biological clock that controls a living organism’s behavior and physiology. The rhythms, which are synchronized with the Earth’s rotation, govern a slew of critical functions, including metabolism, blood pressure, body temperature, and hormone levels. While people have been aware of the body’s “inner clock” for centuries, the three Nobel laureates—Jeffrey Hall, Michael Rosbash, and Michael Young—identified the mechanisms behind it. Working with fruit flies, they isolated a gene that encodes a protein that accumulates in cells at night but degrades during the day. They later identified two other genes that contribute to this process. Their findings help explain why consistently overriding circadian rhythms—by working night shifts or exposing yourself to light from computer screens at night—could increase the risk for chronic health issues, including heart disease, obesity, cancer, and Alzheimer’s. “We learned we are truly rhythmic organisms,” Young tells The Washington Post. “It’s hard to find a cell that does not oscillate in response to these clocks.”

10-13-17 A dementia smell test
A dementia smell test
People with a poor sense of smell may be more likely to develop dementia, a new study suggests. Researchers at the University of Chicago tested how well 2,906 men and women between the ages of 57 and 85 could detect five different scents: peppermint, fish, orange, rose, and leather. Most of the participants were able to identify four to five of the smells, but 22 percent couldn’t. Five years later, the researchers found that those who didn’t pick up at least four of the odors were more than twice as likely to have dementia—even if they had normal brain function when the study began. The worse their performance on the smell test, the higher their risk. “This is not a simple, single-variable test for the risk of dementia,” researcher Jayant Pinto tells The New York Times. “But sensory function is an indicator of brain function. When sensory function declines, it can be a signal to have a more detailed examination to see if everything’s OK.”

10-13-17 The rise of obesity-related cancers
The rise of obesity-related cancers
Heart disease and diabetes aren’t the only chronic health issues obese people should worry about: New research shows that cancers related to being overweight now account for more than a third of all diagnoses of the disease in the U.S. In a review of data from the U.S. Cancer Statistics database, the Centers for Disease Control and Prevention (CDC) found that rates of obesity-linked cancers increased by 7 percent between 2005 and 2014, a period when diagnoses of cancers with no link to obesity decreased by 13 percent. The one exception was colorectal cancer, rates of which dropped by 23 percent, likely due to dramatic improvements in screenings for precancerous growths. Overall, there are 13 different forms of cancer tied to excess body fat. They include multiple myeloma and colorectal cancer, as well as cancers of the brain, esophagus, breast, ovaries, uterus, thyroid, gallbladder, kidney, stomach, liver, and pancreas. “There are many good reasons to strive for a healthy weight,” the CDC’s Anne Schuchat tells Reuters.com. “Now you can add cancer to the list.” Scientists are still working to understand exactly how obesity affects the risk for certain cancers. Research suggests that being overweight triggers chronic low-level inflammation that could lead to DNA damage. Obese people also have higher levels of estrogen and insulin, which are associated with several forms of cancer.

10-13-17 Surgeon aims to diagnose deformities of extinct saber-toothed cats
Surgeon aims to diagnose deformities of extinct saber-toothed cats
At the La Brea Tar Pits in today’s Los Angeles, mastodons, dire wolves, saber-toothed cats and thousands of other creatures — prey and predators — were trapped and later excavated. Robert Klapper has examined scores of damaged and diseased human knees, hips and shoulders. But a visit to the La Brea Tar Pits and Museum introduced the orthopedic surgeon to the suffering of an extinct cat — and a scientific mystery. In 2000, Klapper took a break from his patients at Cedars-Sinai Medical Center in Los Angeles to visit the nearby tar pits, where myriad mammals and other animals (SN: 5/17/14, p. 18) have been getting stuck for the last 40,000 years. (Yes, modern birds and insects still wander in.) After examining a museum display of broad-snouted dire wolf (Canis dirus) skulls, Klapper made a beeline for the security guard and asked to see a curator. He badgered then collections manager Chris Shaw with questions about why the skulls looked so perfect — no signs of cancers, fractures or arthritis. “Instead of throwing me out,” Klapper says, Shaw took Klapper into the bowels of the museum and pulled out a drawer of bones from saber-toothed cats (Smilodon fatalis), one of the abundant prehistoric animals preserved in the pits about 14,000 years ago. Klapper noticed a pelvis with a surface that reminded him of a medieval mace: One hip socket was spiky with sharp edges, a telltale sign of arthritis. At the healthy hip socket, the bone was billiard ball smooth.

10-13-17 We’ve drawn iconic sail-wearing Dimetrodon wrong for 100 years
We’ve drawn iconic sail-wearing Dimetrodon wrong for 100 years
Dimetrodon, one of the most recognisable of the pre-dinosaur predators, might not actually have crawled across the ground as it’s usually depicted. Dimetrodon, one of the most recognisable of the pre-dinosaur predators, is due a makeover. For more than a century, it has been depicted as a sluggish, belly-dragging beast with sprawling legs – but it might actually have held its legs in a more upright position and kept its stomach off the ground as it walked. Often mistaken for a dinosaur, Dimetrodon actually belonged to a group called the pelycosaurs that were more closely related to mammals. It lived between about 290 and 272 million years ago, with some species measuring more than 3 metres from nose to tail. Its most iconic feature was a gigantic sail on its back, the function of which is still debated. Nineteenth Century artists drew Dimetrodon as a sluggish-looking animal with legs sprawled out to each side of its body, resting its weight on an enormous belly – and even in the 21st century nothing much has changed. “I was baffled as I was going through the literature how little this had been questioned,” says Caroline Abbott at the College of William & Mary in Williamsburg, Virginia. It’s particularly surprising given that the fossil trackways left by Dimetrodon seem to tell a different story. The relatively narrow distance between left and right sets of footprints suggest Dimetrodon did not have sprawling legs. “That’s where the real head-scratcher is,” says Abbott. “The trackways are more narrow than you’d expect and in a lot of cases they lack belly dragging marks.”

10-13-17 Did meteorites help start life?
Did meteorites help start life?
Almost 150 years after Charles Darwin theorized that life on Earth may have first formed in “some warm little pond,” new research suggests he may have been right. There are currently two competing theories on the origins of life. The Darwin school of thought posits that during Earth’s early days, meteorites from the solar system deposited compounds that led to the formation of RNA, a compound similar to DNA. The other theory is that life originated much later, in mineral-rich hydrothermal vents on the ocean floor. To explore the plausibility of the former, researchers created a comprehensive model that accounted for the astronomical, geological, chemical, and biological conditions of early Earth. They calculated that tepid, shallow ponds all over the planet could have enabled the essential components of nucleotides to bond, reconfigure, and eventually form long strands of RNA. The researchers believe this process took place at least 4.17 billion years ago—millions of years before the appearance of the earliest known life. But proponents of the hydrothermal vent theory remain unconvinced, arguing it’s unlikely the precursor compounds could have survived the meteorite impact. “It’s definitely another piece of evidence to add to the stacks,” lead author Ben Pearce, from McMaster University in Canada, tells Newsweek.com. “It will take a whole [lot] more science to really nail this down.”

10-12-17 A potential drug found in a sea creature can now be made efficiently in the lab
A potential drug found in a sea creature can now be made efficiently in the lab
This molecule is made naturally in marine critters but is hard to gather in large enough amounts. A bryozoan called Bugula neritina is a natural source of bryostatin 1, which has been studied as a potential drug for many years. A seaweed-like marine invertebrate contains a molecule that has piqued interest as a drug but is in short supply: Collecting 14 tons of the critters, a type of bryozoan, yields just 18 grams of the potential medicine. Now, an efficient lab recipe might make bryostatin 1 easier to get. Making more of the molecule could help scientists figure out whether the drug — which has shown mixed results in limited clinical trials for cancer, HIV and Alzheimer’s disease — will pan out or bomb. Bryostatin 1, found naturally in a sea creature called Bugula neritina, has been studied as a potential drug for several decades. It interacts with an enzyme in the human body that helps regulate cell growth and control immune response. But finding a way to re-create the molecule in the lab, which would ensure a steady supply for research, has been a challenge. It’s a large, unwieldy molecule with a complex structure — multiple rings and lots of appendages with different chemical properties. The new recipe, reported in the Oct. 13 Science, has so far produced more than 2 grams of bryostatin 1.

10-12-17 Gene study shows human skin tone has varied for 900,000 years
Gene study shows human skin tone has varied for 900,000 years
An analysis of genetic variation and skin pigmentation suggests that some particularly dark skin tones evolved relatively recently from paler genetic variants. Skin tone has varied greatly among humans for at least the last 900,000 years. So concludes an analysis of the genetic variants associated with skin pigmentation in people from several regions of Africa. The latest findings suggest that some particularly dark skin tones evolved relatively recently from paler genetic variants, underlining how deeply flawed the racist concept of people with whiter skin being “more advanced” really is. Nicholas Crawford and Sarah Tishkoff at the University of Pennsylvania in Philadelphia recruited around 1500 ethnically and genetically diverse volunteers living in Ethiopia, Tanzania and Botswana for their study. Each person agreed to provide a DNA sample and have their skin pigmentation measured (pictured above). The combined data allowed the team to find eight sites in the human genome that are particularly associated with the level of skin pigmentation. Together, these sites account for about 30 per cent of the variation they found in skin pigmentation among the volunteers. For each of the eight sites of variation, there existed a genetic variant associated with paler skin, and a variant linked to darker skin. Seven of the paler skin variants emerged at least 270,000 years ago. Four of these arose more than 900,000 years ago. The latest thinking is that Homo sapiens emerged in Africa about 300,000 years ago. The new findings mean that relatively pale skin tone variants predate the appearance of our species and have been retained in some parts of Africa ever since.

10-12-17 Blind cave fish lost eyes by unexpected evolutionary process
Blind cave fish lost eyes by unexpected evolutionary process
The discovery that a cavefish might have lost its sight because key eye genes were switched off via epigenetics, rather than mutation, will fuel an evolutionary debate. We’ve found out why a Mexican cavefish has no eyes – and the surprising answer is likely to be seized upon by those who think the standard view of evolution needs revising. Over the past few million years, blind forms of the Mexican tetra (Astyanax mexicanus) have evolved in caves. Maintaining eyes and the visual parts of the brain uses lots of energy, so the loss of eyes is a big advantage for animals living in the dark. Instead the cavefish “see” by sucking. It was assumed that these fish became blind because mutations disabled key genes involved in eye development. This has been shown to be the case for some other underground species that have lost their eyes. But Aniket Gore of the US’s National Institute of Child Health and Human Development and colleagues haven’t found any disabling changes in the DNA sequences of eye development genes in the cavefish. Instead, the genes have been switched off by the addition of chemical tags called methyl groups. This is what is known as an epigenetic, rather than genetic, change. “Although a central role for DNA methylation in development and disease has been well-documented, our results suggest that epigenetic processes can play an equally important role in adaptive evolution,” the team writes. The researchers propose that this epigenetic mechanism allowed the cavefish to shed its eyes faster than if the change had happened via DNA mutations in eye genes.

10-12-17 I spent three days as a hunter-gatherer to see if it would improve my gut health
I spent three days as a hunter-gatherer to see if it would improve my gut health
A London professor travels to Africa to sample a million-year-old diet. Mounting evidence suggests that the richer and more diverse the community of microbes in your gut, the lower your risk of disease. Diet is key to maintaining diversity. This was strikingly demonstrated when an undergrad student went on a McDonald's diet for 10 days and after just four days experienced a significant drop in the number of beneficial microbes. Similar results have been demonstrated in a number of larger human and animal studies. Your gut microbiome is a vast community of trillions of bacteria that has a major influence on your metabolism, immune system, and mood. These bacteria and fungi inhabit every nook and cranny of your gastrointestinal tract, with most of this 1- to 2-kilogram "microbe organ" sited in your colon (the main bit of your large intestine). We tend to see the biggest diet-related shifts in microbes in people who are unhealthy with a low-diversity unstable microbiome. What we didn't know is whether a healthy stable gut microbiome could be improved in just a few days. The chance to test this in an unusual way came when my colleague Jeff Leach invited me on a field trip to Tanzania, where he has been living and working among the Hadza, one of the last remaining hunter-gatherer groups in all of Africa. My microbiome is pretty healthy nowadays and, among the first hundred samples we tested as part of the MapMyGut project, I had the best gut diversity — our best overall measure of gut health, reflecting the number and richness of different species. High diversity is associated with a low risk of obesity and many diseases. The Hadza have a diversity that is one of the richest on the planet.

10-12-17 There’s no rest for the brain’s mapmakers
There’s no rest for the brain’s mapmakers
Grid cells that rats use for navigation remain active even during sleep, studies show. The brain’s mapmaking grid cells keep doing their jobs, even as rats sleep, two new studies find. The brain’s mapmakers don’t get a break, even for sleep. Grid cells, specialized nerve cells that help keep people and other animals oriented, stay on the clock 24/7, two preliminary studies on rats suggest. Results from the studies, both posted October 5 at bioRxiv.org, highlight the stability of the brain’s ‘inner GPS’ system. Nestled in a part of the brain called the medial entorhinal cortex, grid cells fire off regularly spaced signals as a rat moves through the world, marking a rat’s various locations. Individual grid cells work together to create a mental map of the environment. But scientists didn’t know what happens to this map when an animal no longer needs it, such as during sleep. Grid cells, it turns out, maintain their mapmaking relationships even in sleeping rats, report two teams of researchers, one from the University of Texas at Austin and one from the Norwegian University of Science and Technology in Trondheim. (The Norway group includes the researchers who won a Nobel Prize in 2014 for discovering grid cells (SN Online: 10/6/14).) By eavesdropping on pairs of grid cells, researchers found that the cells maintain similar relationships to each other during sleep as they do during active exploration. For instance, two grid cells that fired off signals nearly in tandem while the rat was awake kept that same pattern during sleep, a sign that the map is intact. The results provide insights into how grid cells work together to create durable mental maps.

10-12-17 Perfectly preserved fossil salamander even has last meal in gut
Perfectly preserved fossil salamander even has last meal in gut
A fossil salamander that lived at least 34 million years ago is in such good condition that the remains of a frog it ate are still in its digestive tract. The fossil of an extinct salamander is so exquisitely preserved that the remains of its last meal – a frog – can be seen in its gut. The fossil comes from the site of the Quercy phosphorites in south-west France, which has thrown up many vertebrate fossils over the years. This is despite a large number of specimens probably being destroyed by phosphate mining in the 19th and 20th centuries. The salamander fossil had remained largely forgotten in the French National Museum of Natural History for decades, until Jérémy Tissier of the JURASSICA Museum in Porrentruy, Switzerland, and his colleagues took a closer look. They scanned the fossil using advanced imaging techniques, and named it Phosphotriton sigei after the phosphorus-rich sediments of Quercy. It is the only known fossil of this species, with a search in museums and sediment deposits coming up empty. The salamander died 34 to 40 million years ago, yet aside from its skeleton, many of its soft tissues are preserved: an initial examination identified skin and a lung. These were protected by a process called permineralisation, sometimes loosely known as “mummification”. Under this mechanism, minerals from groundwater seep into a buried animal and fill any empty pockets, or even individual cells. This type of soft tissue preservation is rare, says Dean Lomax at the University of Manchester, UK.

10-11-17 Wake-up call: How a lack of sleep can cause Alzheimer’s
Wake-up call: How a lack of sleep can cause Alzheimer’s
Even a single night of poor sleep can cause changes in the brain implicated in Alzheimer’s. Are you getting enough shut-eye, asks sleep scientist Matthew Walker. I DON’T mean to pry, but how much sleep did you get last night? What about over the past week? I ask because the answer could have serious consequences for your future mental health. More than 44 million people worldwide currently have Alzheimer’s disease, including members of my own family. The health, economic and personal impact is staggering. There has been a marked acceleration in the number being diagnosed with the disease as the human lifespan has increased, but importantly, as total sleep time has decreased. As a sleep scientist, I became interested in this connection some years ago. What I have found is striking. Not only does sleep disruption play a role in the declining mental abilities that typify Alzheimer’s disease, but getting enough sleep is one of the most important factors determining whether you will develop the condition in the future. The implications are huge. We are quickly filling in missing pieces of the Alzheimer’s puzzle, and now we also recognise that sleep offers a route for diagnosis, therapy and even prevention. As we age, our sleep gets worse. This is especially true for the quality of our deep, non-rapid eye movement (NREM) sleep (see chart). Unfortunately, this is the very type of sleep that we now know helps fix new memories into the architecture of the brain, preventing you from forgetting.

10-11-17 Top tips to get a better night’s sleep and improve your health
Top tips to get a better night’s sleep and improve your health
Sleep scientist Matthew Walker reveals how many hours of slumbering you need, how to make up for a lack of it and gives tips on how to get a better night’s rest. It is becoming increasingly clear that getting enough sleep is vital for our physical and mental well-being. Now, sleep scientist Matthew Walker and others have shown how getting enough sleep is also one of the most important things you can do to protect your brain from Alzheimer’s disease. Here’s his advice on how to sleep better and reap the benefits.

  • What’s worse, fragmented sleep or shorter – but unbroken – sleep?
  • Can you undo the damage if you change your behaviour now? When is it too late?
  • How much sleep is enough?
  • What are your tips on getting a good night’s sleep?
    1. Regularity: Go to bed and wake up at the same time, no matter what. Even if you’ve had a bad night of sleep, or it’s the weekend.
    2. Temperature: Keep it cool.Your body needs to drop its core temperature by approximately 1.2 degrees Celsius to initiate sleep.
    3. Light: Dim your lights before bed. Switch off as many lights as possible in the last hour before bed so as not to interfere with natural production of the sleep hormone melatonin.
    4. Walk it out: Never lie awake in bed for a significant period of time (more than 20 minutes or so).
    5. Pass on the espresso and nightcap: Avoid caffeine after 1pm, and no alcohol after 5 or 6pm.

10-11-17 Most versatile stem cell ever may help us understand miscarriage
Most versatile stem cell ever may help us understand miscarriage
The first stem cells capable of making placenta could enable researchers to better understand the biological mechanisms behind many failed early pregnancies. The most versatile stem cells ever created could enable researchers to better understand the biological mechanisms behind many failed early pregnancies. Pentao Liu of the Sanger Institute in Cambridge, UK, and his team developed the stem cells from cells taken from very young mouse embryos. They gave these cells a cocktail of chemicals to prevent them from maturing, trapping them in a very young, primordial state. The team has named them “expanded-potential stem cells” (EPSCs), because – unlike any other stem cells in the lab – they are able to create placenta and yolk sac tissue. These tissues are essential for supporting embryonic and fetal development, and many pregnancies fail because of unknown problems with these tissues. Liu’s team also found that the same chemical cocktail can rewind other types of stem cell back to the same primordial state as EPSCs. This means that researchers should be able to turn embryonic stem cells (which are taken from older embryos) and induced pluripotent stem cells (which are created from mature cells from skin or elsewhere) into EPSCs. “We can erase all memories in these cells and take them back to the equivalent of a blank piece of paper,” says Liu. “This is very exciting research that lays the foundation for generating EPSCs from human embryos,” says Jan Brosens of the University of Warwick. “Such a resource would enable us to study how the developing embryo could be protected from an adverse womb environment and potentially lead to new treatments to prevent recurrent miscarriage.”

10-11-17 Caesarean sections cause obesity and microbiome changes in mice
Caesarean sections cause obesity and microbiome changes in mice
For the first time, researchers have shown that being born by C-section can contribute to obesity in mice. The effect seems to be stronger in females. For the first time, researchers have shown that being born by C-section can contribute to obesity in mice. This probably happens because the procedure disrupts a newborn’s microbiome. Until fairly recently, babies were thought to be born with sterile guts free from bacteria. But we now know that babies are born with a gutful of microbes, and that at least some of these come from a mother’s vaginal canal during birth. Babies born by C-section are thought to miss out on these bacteria, which could explain why their microbiomes look different. The ecosystem of microbes that live inside us has been implicated in a range of health issues, so this may explain why babies born by C-section are more likely to grow up overweight, and to develop allergies and asthma in later life. To test if C-sections really do lead to heavier babies, Maria Dominguez-Bello at New York University and her colleagues performed C-sections on 34 pregnant mice, and compared the resulting pups to 35 that were born vaginally. By the time the mice had grown into adults 15 weeks later, there were stark difference in body weight between the two groups. The mice born by C-section were, on average, 33 per cent heavier than those born vaginally. Females seemed particularly affected, says Dominguez-Bello. While the C-section males were around 20 per cent heavier than their vaginally-born counterparts, the females were 70 per cent heavier, she says. “We were very surprised to see this,” she says. “We have no idea why it’s happening.”

10-11-17 In many places around the world, obesity in kids is on the rise
In many places around the world, obesity in kids is on the rise
An estimated 124 million boys and girls are now in the highest weight range. The rise in childhood obesity around the world has been especially rapid in parts of Asia. Over the last 40 years, the number of kids and teens with obesity has skyrocketed worldwide. In 1975, an estimated 5 million girls and 6 million boys were obese. By 2016, those numbers had risen to an estimated 50 million girls and 74 million boys, according to a report published online October 10 in the Lancet. While the increase in childhood obesity has slowed or leveled off in many high-income countries, it continues to grow in other parts of the world, especially in Asia. Using the body mass index, a ratio of weight to height, of more than 30 million 5- to 19-year-olds, researchers tracked trends from 1975 to 2016 in five weight categories: moderate to severe underweight, mild underweight, healthy weight, overweight and obesity. The researchers defined obesity as having a BMI around 19 or higher for a 5-year-old up to around 30 or higher for a 19-year-old. Globally, more kids and teens — an estimated 117 million boys and 75 million girls — were moderately or severely underweight in 2016 than were obese. But the total number of obese children is expected to overtake the moderately or severely underweight total by 2022, the researchers say.

10-11-17 What modern society can learn from birdsong
What modern society can learn from birdsong
There are a lot of social lessons to be learned from listening to the birds. We are surrounded by cultural products: cities, technologies, the arts, and music. But culture is also deep inside us, in our ability to speak, in our sense of belonging, in our values. The capacity of our brain to adapt to and integrate culture is what makes us human: from birth, your mind was set to absorb concepts, technologies, and social conventions that accumulated over thousands of generations. Feral children, deprived of human society during early life, can rarely recover, and often remain dysfunctional throughout their lives. In contrast, a socially isolated kitten will develop into a fairly normal, functional cat. Yet cultures can be seen (and heard) in many non-human animals. Studying them reveals some of the mechanisms through which our own culture has evolved. Cultures are not just the passive accumulation of customs and traditions; they are formed, and then sustained by a fine balance between social forces. And we can learn from other species about the biological origin of those forces — as well as how these forces are now shaping the future of our culture. What are the social forces through which cultures come about? Culture often starts with an innovation by one animal, which then spreads, as neighbors adopt and modify the successful behaviors they observe. Some cultures, like social norms, are sustained by obedience. Individual vervet monkeys, for instance, can learn fast, but as a group, they have rigid norms: Some food is allowed, while other, perfectly good food is strictly avoided. When juvenile males migrate to a new group, they promptly drop their old feeding habits and obey the new group's norms, with almost 100 percent conformity.

10-11-17 Mass extinctions 'offer cautionary tale'
Mass extinctions 'offer cautionary tale'
Mass extinctions have the potential to guide modern conservation efforts, say scientists. A study confirms the idea that upheavals of the geological past caused a drastic loss of biodiversity. ''Disaster faunas'' dominated by a small number of widespread, newly-evolving species prevailed for millions of years. Researchers warn that a sixth mass extinction is underway, which is predicted to have similar effects. ''These common trends observed in the fossil record have the potential to inform modern conservation efforts, given that the current biodiversity crisis is acknowledged as representing another mass extinction event,'' say the experts. Their work is published in the journal Nature Communications. The study analysed long-term changes in biodiversity in the supercontinent Pangaea, which incorporated almost all of the land masses on Earth. The scientists traced the history of almost 900 animal species living between about 260 million and 175 million years ago. This period witnessed two mass extinctions and the origins of mammals, dinosaurs, crocodiles and turtles. The mass extinction about 252 million years ago was the largest in the Earth's history, in which 70% of land-living animals went extinct.

10-10-17 We’re more Neandertal than we thought
We’re more Neandertal than we thought
Inherited genes from the extinct hominids linked to sunburns, being a night owl. Some people may have inherited a tendency to sunburn from Neandertals, a new study finds. Modern people of European and Asian ancestry carry slightly more Neandertal DNA than previously realized. About 1.8 to 2.6 percent of DNA in non-Africans is an heirloom of ancient human-Neandertal interbreeding, researchers report online October 5 in Science. That corresponds to 10 to 20 percent more Neandertal ancestry than previous estimates — and it may carry consequences for human health and behavior, say paleogeneticist Janet Kelso of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and colleagues. Analysis of DNA from an about 50,000-year-old Neandertal woman from Vindija Cave in Croatia allowed Kelso and colleagues to find the extra ancestry contribution. Among the gene variants modern humans inherited from Neandertals are ones associated with higher cholesterol, increased belly fat, rheumatoid arthritis and schizophrenia, researchers learned from analysis of the new Neandertal DNA. An increased risk of sunburning as a child and a propensity to be an evening person may also be Neandertal legacies, Kelso and Max Planck colleague Michael Dannemann report in a separate study published October 5 in the American Journal of Human Genetics. Their analysis — which used DNA data from a Neandertal woman from the Altai Mountains in Siberia (SN: 1/25/14, p. 17) and 112,338 present-day British people — confirmed some links between Neandertal heritage and human diseases made by previous studies (SN: 3/5/16, p. 18), but didn’t find evidence that Neandertal gene variants contribute to obesity.

10-10-17 Human hearts kept ‘asleep’ in a box can survive outside the body
Human hearts kept ‘asleep’ in a box can survive outside the body
A new way of storing hearts outside the body for a day or more could bring an end to people dying while awaiting an organ for a heart transplant. A new way of keeping hearts alive but “asleep” in a box outside the body for a day or more could bring an end to people dying on the heart transplant waiting list. The system was tested on the first patient in August, albeit with the heart kept in this state for just 3 hours, New Scientist can reveal. It will be tested on another five people for this same time and, if all goes well, the time will be gradually raised to 24 hours. Stig Steen at Lund University in Sweden, who developed the technique, says it could potentially be used for up to several days. Any ability to keep hearts alive for longer outside the body boosts the number available for transplants. There is a shortage of all organs for transplant, with over a thousand people in the UK dying every year for want of one. In England, the shortfall may be eased by the forthcoming switch to an “opt-out” system of organ donation, announced last week. But it won’t disappear, partly because only a fraction of people who die in hospital have organs suitable for donation, and families will still be able to override their relatives’ wishes. With hearts, a particular problem is distance between the donor and the patient, because hearts can only be kept alive outside the body for a few hours before weakening. “Now we say no to a lot of good hearts,” says Steen. “With the new way, we can take hearts from theoretically the whole world. We can get the perfect fit for each patient.”

10-10-17 New deep-sea sponge could play a starring role in monitoring ocean health
New deep-sea sponge could play a starring role in monitoring ocean health
Plenaster craigi grows on metal-filled rocks that are a target for mining. Sponges encrusting deep-sea, metal-filled rocks were identified as a new species, in part due to their dense mass of star-shaped parts called spicules, seen in closeup here. The deep waters of the East Pacific hold an unprepossessing treasure trove: Potato-sized lumps of rock that contain valuable metals such as manganese, cobalt and copper. Turns out, such “manganese nodules” are home to another kind of goody: a species of sponge never before seen, researchers report online September 24 in Systematics and Biodiversity. These newly discovered nodule-dwellers may help scientists monitor the impact of future deep-sea mining. Little is known about life in the abyssal depths of the ocean, 4,000 to 6,000 meters down. But the prospect of mining in those depths is looming: For example, the United Nation’s International Seabed Authority has granted 16 exploration contracts for mining manganese nodules. To track how mining will affect deep-sea ecosystems over time, scientists are eager to establish a baseline of existing biodiversity in regions such as the Clarion-Clipperton Zone (CCZ), an area in the eastern Pacific Ocean littered with the nodules.

10-10-17 Drone designers accidentally explain colour of albatross wings
Drone designers accidentally explain colour of albatross wings
Why are some birds' wings darker on top? Engineers may have found the answer while trying to design a biomimetic drone that goes further on less fuel. IT’S not every day that an aerospace engineer raises new questions about bird flight. But Abdessattar Abdelkefi and his team at New Mexico State University did just that while trying to devise better drones. Many large soaring birds like the albatross have wings that are white underneath and black on top. Previous explanations focused on camouflage, says Graham Martin at the University of Birmingham, UK. But does that colouring really boost endurance in flight? Most soaring needs no flapping of wings; instead, the bird exploits air currents to glide. Abdelkefi’s team discovered that a wing’s black upper surface absorbs sunlight very efficiently, causing it to be around 10°C warmer than the lower surface. That effectively lowers air pressure on the upper surface, lowering drag and generating extra lift (Journal of Thermal Biology, doi.org/f96ggw). Svana Rogalla at the University of Ghent, Belgium, says thermography has proved that the dark upper wing gets hotter in sunlight, but it is too early to pin down its effect on drag. The impact of colour on flight could be a further inducement for birds to make costly melanin pigment to darken feathers, she says. The team hopes the findings will help them design more efficient and durable drones for use at sea.

10-10-17 Singapore scientists reveal origins of durian's pungent aroma
Singapore scientists reveal origins of durian's pungent aroma
One of nature's smelliest secrets may have been revealed, thanks to a dedicated team of durian-loving scientists in Singapore. Researchers have found an odour gene which gives the thorny fruit its notoriously pungent scent. The discovery meant the possibility of creating "odourless or milder-tasting" fruits in future, the scientists said. It has sparked mixed feelings from durian aficionados, who worship its signature rank smell. "A durian without its smell is nothing but an empty shell with no essence," wrote Singaporean Richie Liang on Facebook, who also compared "a durian without its unique smell" to "a human being who has lost his or her soul". After three years of research, privately funded by a group of anonymous durian lovers, the five-man team of cancer scientists now have a complete genetic map of the fruit, a world first. Their findings were published in academic journal Nature Genetics. "Our analysis revealed that volatile sulphur production is turbocharged in durians, which fits with many people's opinions that durian smell has a 'sulphury' aspect," said geneticist Patrick Tan, who co-led the study. The researchers said the durian's distinctive odour served an important purpose to it in the wild: helping to attract animals to eat it and disperse its seeds.

10-10-17 New evidence on how birds took to the air
New evidence on how birds took to the air
New fossil evidence has pushed back a key step in the evolution of bird flight by millions of years. Skeletal changes that helped birds take to the air happened 120 million years ago, during the hey day of dinosaurs, according to a specimen from China. Features such as fused bones were thought to be present only in relatively advanced birds, living just before the dinosaurs went extinct. A strong, rigid skeleton is part of the blueprint of modern birds. The bird, Pterygornis dapingfangensi, lived in north-eastern China during the Early Cretaceous. It is only the second of its kind to be discovered and is exquisitely preserved. The find ''pushed back the date for these birds' features by over 40 million years,'' said co-researcher, Min Wang from the Institute of Vertebrate Palaeontology and Palaeoanthropology at the Chinese Academy of Sciences in Beijing. One of the requirements of all flying machines is a structure that is both strong and lightweight. To achieve this in birds meant changes to the basic body plan of most back-boned animals. During the course of bird evolution, some of the vertebrae and bones of the pelvic girdle fused together, as did some finger and leg bones. And many tail, finger, and leg bones were lost. The specimen is the oldest known bird fossil with fully fused hands and pelvic girdles, said Dr Steve Brusatte of the University of Edinburgh, who reviewed the scientific paper, published in the journal PNAS.

10-9-17 Evolution’s rules mean life on Earth isn’t that varied after all
Evolution’s rules mean life on Earth isn’t that varied after all
While there are millions of species on Earth, many of them have almost identical lifestyles, suggesting nature is more regular and rule-based than we thought. Many seemingly different species actually live very similar lives. This convergence suggests that it may someday be possible to predict how many species live in a particular habitat, and even to identify the holes left by missing species. For more than half a century, ecologists have tended to describe ecological roles, or “niches”, as though they were properties of individual species. For example, chameleons are camouflaged, tree-dwelling lizards that ambush insects, while horned lizards are ground-dwelling desert creatures that eat ants and bear protective spines. The diversity can seem overwhelming. But Eric Pianka, an evolutionary ecologist at the University of Texas in Austin, has long wondered whether there might only be a certain, limited set of niches. To test the idea, Pianka and his colleague Laurie Vitt at the University of Oklahoma decided to pool their decades of experience studying lizards in the field. “Our entire life, basically, has been going out and collecting data on lizards,” says Vitt. “So we have a huge data set.” The pair looked at 134 species on four continents. For each one, they examined more than 50 features of their niches, such as habitat type, hunting style, reproductive output and defences against predators. Then, with colleagues, they crunched the numbers. Over and over, they saw pairs of unrelated lizards converge on similar niches. Out of the 134 species, 100 belonged to a convergent pair, far more than could have happened by chance.

10-9-17 Cold climate may have driven ancient humans’ move out of Africa
Cold climate may have driven ancient humans’ move out of Africa
East Africa became colder and drier around 75,000 years ago, just when modern humans were apparently migrating out of Africa. Ancient humans may have trekked out of Africa to escape arid climes. This is the result suggested by a record of climate in East Africa spanning the past 200,000 years. “It raises the possibility that drought, rather than rainy conditions, prompted early humans to migrate,” says lead author Jessica Tierney at the University of Arizona. Modern humans are widely agreed to have evolved in Africa and are thought to have migrated out 65,000 to 55,000 years ago. They may have left via East Africa and headed to Arabia, although this isn’t settled. Previous studies showed that many parts of Africa, like the Sahara, have had many wet and dry periods. A marine core, collected from the Gulf of Aden off Africa’s east coast in 1965, has sediments dating to 200,000 years ago. Analysing this allowed Tierney and her colleagues to construct an extended timeline of climate shifts in north-east Africa. They focused on a chemical called alkenone that is made by marine algae, whose composition changes as the temperature of the sea surface alters. In this way, they determined temperatures every 1600 years, going back 200,000 years. The team also created a rainfall record by analysing the wax of leaves blown out to sea and buried in the sediment. Plants make subtly different leaf wax depending on rainfall. Between 130,000 and 80,000 years ago, the team found that north-east Africa was warm and wet, in line with previous evidence. But between 75,000 and 55,000 years ago, the climate turned dry and cold – and genetic studies suggest this is when the major out-of-Africa migration happened.

10-9-17 Ancient whale turns up on wrong side of the world
Ancient whale turns up on wrong side of the world
The rarely seen pygmy right whale may once have cruised northern waters. Today, pygmy right whales live in the Southern Hemisphere. But two new fossils suggest that the species lived for a time in the Northern Hemisphere. A new discovery is turning the hemispheric history of a mysterious whale species upside-down. Two fossils recently unearthed in Italy and Japan suggest that a southern whale was briefly a denizen of northern waters more than half a million years ago. Until now, all available evidence suggested that the pygmy right whale, Caperea marginata, and its ancestors have been steadfast Southern Hemisphere residents for the past 10 million years. Pygmy right whales are so rarely sighted that scientists know very little about their lifestyle, and the fossil record is sparse, too. The new Northern Hemisphere fossils both closely resemble other confirmed specimens of the whales, researchers report October 9 in Current Biology. The fossils include a fragmented skull with ear bones dating to 0.5 to 0.9 million years ago, and a bone containing parts of the middle and inner ear that’s 1.7 million to 1.9 million years old. Glaciation near the South Pole during the Pleistocene Ice Age may have temporarily pushed Caperea further north, the researchers propose. Then, as the glaciers melted, the whale migrated south again. Because the new fossils are separated in age by about a million years, it’s hard to say whether the whales crossed the equator multiple times or briefly established a longer-term population in the Northern Hemisphere.

10-9-17 Anti-doping agency to ban all gene editing in sport from 2018
Anti-doping agency to ban all gene editing in sport from 2018
The World Anti-Doping Agency has extended its ban on “gene doping” to include all forms of gene editing – but it’s not clear if WADA will be able to enforce it. The battle between sports cheats and testers is poised to enter a whole new arena. The World Anti-Doping Agency has extended its 2003 ban on “gene doping” to include all forms of gene editing – but it is not clear the agency has the means to enforce this ban. WADA already bans the use of genetically modified cells and gene therapy if they have “the potential to enhance sport performance”. From 2018, the list will also include “gene editing agents designed to alter genome sequences and/or the transcriptional or epigenetic regulation of gene expression”. Gene editing involves tweaking existing genes, rather than adding whole new ones to a person’s body. The field is advancing incredibly fast thanks to the development in 2012 of an easy editing method called CRISPR. The first human trials of the method are already underway. Whether people who have medical treatment involving such methods will be able to later compete in sports depends on the nature of the treatment, says WADA spokesperson Maggie Durand. “Generally, performance enhancement implies enhancement beyond a return to normal, although you may appreciate that this is not always easy to prove definitively,” she says. In cases where a treatment is specifically banned by WADA, athletes will be able to apply for an exemption when gene editing is used for therapeutic use.

10-9-17 Superbugs may meet their match in these nanoparticles
Superbugs may meet their match in these nanoparticles
‘Quantum dots’ mess with bacteria’s defenses, allowing antibiotics to work. By producing a chemical that makes bacteria more vulnerable to antibiotic attack, quantum dots could help reboot medications that have lost their edge against hard-to-kill microbes. Antibiotics may have a new teammate in the fight against drug-resistant infections. Researchers have engineered nanoparticles to produce chemicals that render bacteria more vulnerable to antibiotics. These quantum dots, described online October 4 in Science Advances, could help combat pathogens that have developed resistance to antibiotics (SN: 10/15/16, p. 11). “Various superbugs are evolving too rapidly to be counteracted by traditional drugs,” says Zhengtao Deng, a chemist at Nanjing University in China not involved in the research. “Drug resistant infections will kill an extra 10 million people a year worldwide by 2050 unless action is taken.” In the study, antibiotics spiked with quantum dots fought off bacteria as effectively as 1,000 times as much antibiotic alone. That’s “really impressive,” says Chao Zhong, a materials scientist at ShanghaiTech University who was not involved in the study. “This is a really comprehensive study.”

10-9-17 The medical mystery of split-brain patients
The medical mystery of split-brain patients
When you split the brain, do you split the person? The brain is perhaps the most complex machine in the universe. It consists of two cerebral hemispheres, each with many different modules. Fortunately, all these separate parts are not autonomous agents. They are highly interconnected, all working in harmony to create one unique being: you. But what would happen if we destroyed this harmony? What if some modules start operating independently from the rest? Interestingly, this is not just a thought experiment; for some people, it is reality. In so-called "split-brain" patients, the corpus callosum — the highway for communication between the left and the right cerebral hemispheres — is surgically severed to halt otherwise intractable epilepsy. The operation is effective in stopping epilepsy; if a neural firestorm starts in one hemisphere, the isolation ensures that it does not spread to the other half. But without the corpus callosum the hemispheres have virtually no means of exchanging information. What, then, happens to the person? If the parts are no longer synchronized, does the brain still produce one person? The neuroscientists Roger Sperry and Michael Gazzaniga set out to investigate this issue in the 1960s and '70s, and found astonishing data suggesting that when you split the brain, you split the person as well. Sperry won the Nobel prize in Medicine for his split-brain work in 1981. How did the researchers prove that splitting the brain produces two persons, one per hemisphere?

10-9-17 Exploding stars could have kick-started our ancestors’ evolution
Exploding stars could have kick-started our ancestors’ evolution
The savannahs early hominins occupied might have appeared thanks to a spate of wildfires 8 million years ago – which might in turn be linked to a nearby supernova. Was the rise of humankind written in the stars? A nearby star exploding 8 million years ago might have triggered more frequent lightning on Earth. Wildfires ignited by that lightning could help explain the rise of east African savannahs – which many researchers think provided a vital backdrop for the early evolution of hominins. The rise of African savannahs, beginning about 8 million years ago, has long been a mystery to biologists. They are dominated by plants called C4 grasses – but those grasses appeared 20 million years ago, long before they rose to dominance. Some botanists now wonder whether the trigger was a spate of wildfires 8 million years ago. Grasses bounce back quickly after a wildfire while trees are slower to recover, so frequent wildfires would have favoured the expansion of savannahs. Now researchers led by Brian Thomas at Washburn University in Kansas, Georg Feulner at the Potsdam Institute for Climate Impact Research in Germany and Adrian Melott at the University of Kansas have provided a possible explanation for the surge in wildfires 8 million years ago. Deep-sea sediments of that age contain a lot of iron-60, which is produced in massive stars. Its presence strongly suggests there was at least one nearby supernova at the time. The team says a pulse of high-energy cosmic rays from the supernova must have swept across Earth.

10-6-17 Little-known drug keeps climbers’ minds sharp at high altitude
Little-known drug keeps climbers’ minds sharp at high altitude
An obscure drug, oxiracetam, seems to boost the brain's blood supply and reduce cognitive deficits caused by altitude, according to a study at 4000 metres. A so-called “smart drug” intended to boost cognitive performance also seems to protect the brain from altitude sickness, according to a military study that tested it at 4000 metres. An increasing number of people visit high-altitude sites nowadays, for work, sport, religious pilgrimages and military tasks. But even the fittest among us suffer in thin air: the lower oxygen content at altitude can lead to cognitive effects, including memory loss and attention difficulties. There is little you can do to prevent these symptoms other than acclimatise – but this takes time and doesn’t always work. A drug called oxiracetam might be the answer. ShengLi Hu at the Third Military Medical University, Chongqing, China, and her colleagues took men from the military up to 4000 metres above sea level. All of the men lived in towns around 1800 metres above sea level. During the study, they spent 8 days at this altitude, before climbing for three days to reach 4000 metres, where they stayed for up to a month. Twenty participants took 800mg of oxiracetam three times per day for the first 15 days of the study, while another 20 men received no intervention. The men performed tests of attention and memory at the start and end of the study and 20 days in, by which time they had been at 4000 metres for nine days. While all participants experienced a drop in cognitive ability at 4000 metres, those who took oxiracetam showed a much smaller decline than the control group.

10-6-17 Europe’s Stone Age fishers used beeswax to make a point
Europe’s Stone Age fishers used beeswax to make a point
This 13,000-year-old fishing spear is the first evidence that northern populations used bee product as glue. Chemical analyses show that a barbed bone point from Germany dating to around 13,000 years ago contains remnants of a beeswax glue near its base. Either honeybees entered northern Europe earlier than thought, as glaciers retreated, or beeswax was traded over long distances, scientists say. Late Stone Age people got a grip thanks to honeybees. Northern Europeans attached a barbed bone point to a handle of some kind with a beeswax adhesive around 13,000 years ago, scientists say. The result: a fishing spear. Using beeswax glue to make tools was common in Africa as early as 40,000 years ago (SN: 8/25/12, p. 16). But this spear is the first evidence of its use in cold parts of Europe at a time toward the end of the Stone Age when the glaciers were receding, say archaeologist Michael Baales of LWL-Arch?ologie für Westfalen in Olpe, Germany, and his colleagues. Where the beeswax came from remains a question. Honeybees may have pushed north into Europe from warmer, Mediterranean locales several thousand years earlier than previously thought, the researchers propose in the October Antiquity. Farmers in Southwest Asia and Europe acquired beeswax and probably honey as early as 9,000 years ago (SN: 12/12/15, p. 13). Or Northern European hunter-gatherers may instead have obtained beeswax through trade networks extending to Mediterranean areas, Baales’ team says. Stone Age Eurasians formed group alliances over large areas (SN Online: 10/5/17).

10-5-17 Parenting advice gets a fact-check
Parenting advice gets a fact-check
Raising babies is a combination of the ridiculous, the joyful and the difficult. And while I am most definitely biased, I suspect that there’s something even more difficult about raising babies in the Information Age. A smartphone can be a powerful tool. Information abounds online, and some of it is excellent. But in the hand of an exhausted, worried new parent, a smartphone can turn ugly. Sometimes, parenting information found online is no good, even though it seems reputable. That’s something I learned firsthand after my first daughter was born. What I would give to have back the hours I wasted scrolling questionable websites and even more questionable parent forums. My struggle to sort good information from bad became the impetus for Growth Curve — a blog based on science, presenting facts (or lack thereof) to help parents make the best decisions for their growing families. So imagine my delight when I heard from the founders of the new website Parentifact.org. It describes itself as “what happens when two journalists have a baby,” and it’s a breath of fresh air for parents who want solid information quickly.

10-6-17 Protein injection could prevent hair loss during chemotherapy
Protein injection could prevent hair loss during chemotherapy
A hair-promoting protein can stop mice from losing fur when given chemo, raising the hope that cancer patients will be able to avoid this side effect. Mice injected with a hair-promoting protein did not lose their hair during chemotherapy. The finding raises the hope that people undergoing cancer treatment can one day avoid this distressing side effect. Hair loss is one of the most feared side effects of chemotherapy. One study of women with breast cancer found that around 8 per cent had considered refusing treatment to save their locks. There are few options for people receiving treatment. Scalp-cooling caps freeze and constrict blood vessels to stop chemo drugs from flowing into hair follicles. But they are expensive, work for only 50 per cent of people, extend treatment by two hours and cause discomfort and headaches. Other people have experimented with using the hair loss treatment minoxidil during chemo, but a randomised controlled trial found no benefit. Part of the problem is our limited understanding of how chemotherapy damages hair follicles, says Sung-Jan Lin at National Taiwan University. To address this, his team looked at the role of a protein called p53. This protein is activated during chemo and helps to suppress tumour growth, but may also suppress hair growth, since hair cells rapidly divide like tumour cells. A previous study found that mice missing the p53 protein did not shed their fur during chemo.

10-5-17 Side effects are worse when we think medication looks expensive
Side effects are worse when we think medication looks expensive
People have been found to experience stronger side effects when a treatment looks more expensive, according to a study of the nocebo effect. Watch the cost. People are more likely to experience stronger side effects when a treatment appears to be more expensive, according to a study of the nocebo effect. While the placebo effect means that some people feel better when they have unknowingly been given a sham or control treatment, the nocebo works the opposite way. Researchers frequently observe nocebo effects in clinical trials, when people who receive a placebo experience negative side effects as if they had been given an actual drug. Placebos are known to have stronger positive effects the more expensive the person receiving them believes them to be. Alexandra Tinnermann, at the University Medical Center Hamburg-Eppendorf, and her colleagues wondered if price might also affect the strength of the nocebo effect. The team created two packages for fake creams and told volunteers that they are used to treat itchy skin. One package looked like an expensive pharmaceutical brand name, while the other looked like a cheaper, generic medication. The participants were shown one of the two creams and told that it was believed to increase a person’s sensitivity to pain as a side effect.

10-6-17 New book offers a peek into the mind of Oliver Sacks
New book offers a peek into the mind of Oliver Sacks
Essays in ‘The River of Consciousness’ tackle evolution, memory and more. In an anthology of wide-ranging essays, neurologist and author Oliver Sacks celebrates the beauty — and mysteries — of the world and the people, animals and plants that inhabit it. The experience of reading the essays that make up The River of Consciousness is very much like peering into an ever-changing stream. Pebbles shift as the water courses by, revealing unexpected facets below. The essays, by neurologist Oliver Sacks and arranged into an anthology two weeks before his death in 2015, meander through such topics as evolution, memory and scientific progress. Most have been published before. But by bringing these quirky, personal and curious essays together, Sacks invites readers into his mind where they can experience the world from his unusually insightful perspective. Some essays are long, some short. Some take a biographical bent, while others focus more on scientific principles. Many explore lesser-known fascinations of scientific luminaries: Charles Darwin’s intense study of flowers, the reader learns, provided some of the best evidence for his theory of evolution. And then, of course, there are Sacks’ own observations. As his death neared, he wrote of his fading hearing, perceiving a story about a big-time publicist diagnosed with amyotrophic lateral sclerosis as a story about a “cuttlefish.” He began keeping a notebook of these mishearings, recording what he heard, what was actually said and people’s reactions.

10-5-17 Ancient humans avoided inbreeding by networking
Ancient humans avoided inbreeding by networking
DNA from 34,000 years ago suggests hunter-gatherers left home to find mates. DNA from four Stone Age people suggests that hunter-gatherers have long formed groups with few close relatives. Aside from discouraging inbreeding, that social structure encouraged cooperative ties among groups and rapid cultural advances, scientists say. DNA of people who lived around 34,000 years ago reveals an especially lively social scene that may have been a key to humans’ evolutionary success. Much like hunter-gatherers today, ancient Eurasians married outside their home groups and formed webs of friends and in-laws vital for eventually building cities and civilizations, a new study suggests. Long-gone hunter-gatherers lived in groups with few close relatives, thus limiting opportunities for inbreeding, say evolutionary geneticist Martin Sikora of the Natural History Museum of Denmark in Copenhagen and his colleagues. It’s likely that adolescents of both sexes found mates in communities other than their own, fostering social ties among groups that might otherwise avoid or fight each other, the scientists conclude online October 5 in Science. Modern hunter-gatherers likewise find partners among nearby groups (SN: 4/9/11, p. 13). Sikora’s findings support a proposal that hunter-gatherer bands composed mainly of in-laws and unrelated individuals appeared by the late Stone Age and probably much earlier than that, says anthropologist Kim Hill of Arizona State University in Tempe, who did not participate in the new study. The emergence of in-laws boosted communication and social learning across groups, a prerequisite for creating civilizations.

10-4-17 We’re nearly ready to use CRISPR to target far more diseases
We’re nearly ready to use CRISPR to target far more diseases
Forget editing embryos. We’re nearly ready to use CRISPR to change DNA inside our own bodies to treat many disorders, from hepatitis B to muscular dystrophy. THE race is on to edit our bodies to fight or prevent disease. Results from animal studies targeting the liver, muscles and brain suggest CRISPR genome-editing could revolutionise medicine, allowing us to treat or even cure a huge range of disorders. This powerful technique for changing DNA was only developed five years ago, but around 20 trials in people have already begun or will soon. However, most of these involve removing cells from a person, editing their DNA, and putting them back into the body. This approach is being used, for example, to alter immune cells to make them better at killing cancers. It’s relatively easy to remove these cells, edit them, and return them to the body, but this isn’t possible for most bodily tissues. So being able to edit cells inside the body without removing them would allow us to treat many more conditions – from genetic disorders to high cholesterol. Absolutely everything could be treated this way, says Irina Conboy of the University of California, Berkeley. The challenge is delivering the CRISPR machinery to tissues inside the body. Editing genes with CRISPR requires at least two components: a protein that cuts DNA and a piece of RNA that guides it to the precise DNA site to make the cut. Proteins and RNAs are much larger than standard drugs and it’s hard to get them inside cells. They don’t usually survive in the bloodstream, either.

10-4-17 We’ve finally seen how the sleeping brain stores memories
We’ve finally seen how the sleeping brain stores memories
For the first time, scans of sleeping people have shown how memories are moved in the brain, and suggest that the first hours of shut-eye are key for memory. AT LAST, we’ve seen how the brain memories when we sleep. By scanning slumbering people, researchers have watched how the “trace” of a memory moves from one region of the brain to another. “The initial memory trace kind of disappears, and at the same time, another emerges,” says Shahab Vahdat at Stanford University in California. It is the first time memories have been observed being filed away in humans during sleep, he says. Vahdat and his colleagues did this by finding people who were able to fall asleep in the confined, noisy space of an fMRI scanner, which is no easy undertaking. “We screened more than 50 people in a mock scanner, and only 13 made it through to the study,” says Vahdat. The team then taught this group of volunteers to press a set of keys in a specific sequence – in the same way that a pianist might learn to play a tune. It took each person between about 10 and 20 minutes to master a sequence involving five presses. “They had to learn to play it as quickly and as accurately as possible,” says Vahdat. Once they had learned the sequence, each volunteer put on a cap of EEG electrodes to monitor the electrical activity of their brain, and entered an fMRI scanner – which detects which regions of the brain are active. The team saw a specific pattern of brain activity while the volunteers performed the key-pressing task. Once they had stopped, this pattern kept replaying, as if each person was subconsciously revising what they had learned.

10-4-17 Luhan Yang strives to make pig organs safe for human transplants
Luhan Yang strives to make pig organs safe for human transplants
Genome editing with CRISPR/Cas9 could circumvent organ rejection problems. Luhan Yang is “exceptionally bold, yet careful,” says George Church, who co-founded eGenesis with Yang. Biologist Luhan Yang dreams of pig organs that will one day fly — into people. If she has her way, animal farms will raise herds of bioengineered pigs, designed to produce kidneys, livers and other organs that could be transplanted into humans. Animal parts would slip seamlessly into people, easing their suffering. “There are millions of patients worldwide waiting for organ transplants,” says Yang, who is chief scientific officer of eGenesis, a biotech start-up in Cambridge, Mass. “It’s such a huge unmet need.” Researchers have long dreamed of using animal organs to alleviate the shortage of human ones, a field called xenotransplantation. So far those efforts have ended in failure, usually with the person’s immune system rejecting the transplanted animal organ. But Yang has both the tools and the drive to change that. She is pioneering the direct editing of mammals’ genetic instruction books, or genomes, working to tweak DNA to make pig organs more acceptable inside humans. All before her 32nd birthday.

10-4-17 KC Huang probes basic questions of bacterial life
KC Huang probes basic questions of bacterial life
The theorist turned experimentalist takes a cross-disciplinary perspective. “My motivating questions are about understanding the physical challenges bacterial cells face,” says Kerwyn Casey Huang. Physicists often ponder small things, but probably not the ones on Kerwyn Casey “KC” Huang’s mind. He wants to know what it’s like to be a bacterium. “My motivating questions are about understanding the physical challenges bacterial cells face,” he says. Bacteria are the dominant life-forms on Earth. They affect the health of plants and animals, including humans, for good and bad. Yet scientists know very little about the rules the microbes live by. Even questions as basic as how bacteria determine their shape are still up in the air, says Huang, of Stanford University. Huang, 38, is out to change that. He and colleagues have determined what gives cholera bacteria their curved shape and whether it matters (a polymer protein, and it does matter; the curve makes it easier for cholera to cause disease), how different wavelengths of light affect movement of photosynthetic bacteria (red and green wavelengths encourage movement; blue light stops the microbes in their tracks), how bacteria coordinate cell division machinery and how photosynthetic bacteria’s growth changes in light and dark. All four of these findings and more were published in just the first three months of this year.

10-4-17 Lena Pernas sees parasitic infection as a kind of Hunger Games
Lena Pernas sees parasitic infection as a kind of Hunger Games
Mitochondria may lead cell’s attempt to keep nutrients from the invader. “Toxoplasma is a pretty incredible bug,” says Lena Pernas. But studying the parasite requires gloves, lab coats and goggles. “I wanted hazmat suits.” Lena Pernas’ love of parasites began in childhood, when she was plagued with many virtual infections. One of her favorite pastimes as a 9-year-old was playing The Amazon Trail, an educational computer game set near the South American river. One of the dangers players could encounter was malaria, “and I got malaria a lot,” Pernas says. This predicament inspired her to learn about the disease, caused by Plasmodium parasites. Since then, she’s taken every opportunity to study parasites. “It’s been a singular obsession,” she says. Her parasite of choice eventually became Toxoplasma gondii, which is estimated to infect one-third of humans. Toxoplasma “has an unparalleled mammalian host range,” Pernas says. “It is able to infect basically any warm-blooded animal.” The parasite causes toxoplasmosis, not a terribly bothersome disease for people with a healthy immune system. But the disease can be serious, damaging the eyes and brain, in those with weakened immune systems and in fetuses. (Pregnant women are warned not to handle kitty litter because the parasite can be found in cat feces.)

10-4-17 Your ‘risk intelligence’ decides how much of a daredevil you are
Your ‘risk intelligence’ decides how much of a daredevil you are
The most comprehensive study yet into how people respond to risk has found that there is a common factor that drives all types of risk-taking. If your new boyfriend smokes, will he risk your relationship for the thrill of a one-night stand? What if your accountant likes to go base jumping at the weekend – might she be more likely to take risks with your money than someone who relaxes by playing golf instead? The answer to both seems to be yes. The most comprehensive study yet into how people respond to risk has found there is a common component that drives all types of risk-taking. How eager we are to engage in risky activities is known as our risk preference. Psychologists consider this a key component of human behaviour because its impact on our decision-making has consequences – often dramatic ones – for so many aspects of our lives. Despite its importance, there is a lack of consensus over whether people’s tendency to take risks is consistent or whether it varies depending on the type of risk. To find out, Renato Frey at the University of Basel in Switzerland and his colleagues asked 1500 adults to complete 39 tests commonly used to measure risk preference in different scenarios. Controlling for age and gender, they found that 61 per cent of the variation in an individual’s scores across the tests could be explained by a single component, with the rest of the variation explained by factors specific to the different types of risk.

10-4-17 Different meditation types train distinct parts of your brain
Different meditation types train distinct parts of your brain
Just like physical exercise, the kind of improvements you get with meditation depend on exactly how you train. We are used to hearing that meditation is good for the brain, but now it seems that not just any kind of meditation will do. Just like physical exercise, the kind of improvements you get depends on exactly how you train – and most of us are doing it all wrong. That the brain changes physically when we learn a new skill, like juggling or playing a musical instrument, has been known for over a decade. Previous studies had suggested that meditation does something similar for parts of the brain involved in focused attention. Two new studies published in Science Advances suggest that certain kinds of meditation can change social and emotional circuitry, too. The research comes out of the ReSource Project at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany, and looked at the effects of three different meditation techniques on the brains and bodies of more than 300 volunteers over 9 months. One technique was based on mindfulness meditation, and taught people to direct attention to the breath or body. A second type concentrated on compassion and emotional connection via loving kindness meditations and non-judgmental problem-sharing sessions with a partner. A final method encouraged people to think about issues from different points of view, also via a mix of partnered sessions and solo meditation. In one study, MRI scans taken after each three-month course showed that parts of the cortex involved in the specific skill that was trained grew thicker in comparison with scans from a control group.

10-4-17 Our braininess may have evolved thanks to less sticky neurons
Our braininess may have evolved thanks to less sticky neurons
We don’t know much about the genetic evolution of the human brain. Now experiments suggest genes involved in cell stickiness may have given our brain its folds. OUR braininess may have evolved thanks to gene changes that made our brain cells less sticky. The cortex is the thin, highly folded outer layer of our brains and it is home to some of our most sophisticated mental abilities, such as planning, language and complex thoughts. Around three millimetres thick, this layer is folded into an intricate pattern of ridges and valleys, which allows the cortex to be large, but still fit into a relatively small space. Many larger mammals, such as primates, dolphins and horses, have various patterns of folds in their cortex, but folds are rarer in smaller animals like mice. So far, we have only identified a few genetic mutations that contributed to the evolution of the human brain, including ones that boosted the number of cells in the cortex. One theory about how the cortex came to be folded is that it buckled as the layer of cells expanded. Daniel del Toro at the Max Planck Institute of Neurobiology in Munich, Germany, and colleagues wondered if some of the genetic changes in our brain’s evolution might have been about more than just an increasing number of cells. They investigated the genes for two molecules – FLRT1 and FLRT3 – which make developing brain cells stick to each other more.

10-4-17 Why are humans so hairy?
Why are humans so hairy?
This is an extract from How To Be Human, our new illustrated book about the most amazing species on the planet (John Murray). Human hair is decidedly strange. Most of our body hair is so wispy and short as to be almost invisible, though in some places it is coarse and curly. Our head hair is almost uniquely long and flamboyant. We are pretty much the only animal to have hair that grows continuously for many years, and also to suffer the indignity of going bald. No wonder our relationship with our hair is a tangled one. Human hair comes in two basic types: terminal hair, which grows on the scalp, eyebrows and eyelashes, and vellus hair, which is found everywhere else. Beyond that, the main difference between hair types is how long they grow for before the follicle runs out of steam. This is what determines their length and thickness. Hair follicles go through cycles of growth and dormancy. During the growth phase the hair grows continuously at about 0.4 millimetres per day, getting longer and thicker in the process. But at some point the hair-producing cells die off and growth stops. The hair falls out and the follicle goes dormant for around six months before sprouting new hair-producing cells and entering a new growth phase. The length of the growth phase is controlled by hormones. Leg hairs grow for about two months, which is why they are short and fine. Armpit hairs make it to six months, but head hairs grow non-stop for six years or more. That means head hair can theoretically grow to almost a metre in length. Ideas abound as to why evolution has endowed us with such a unique combination of hair types.

10-4-17 Christina Warinner uncovers ancient tales in dental plaque
Christina Warinner uncovers ancient tales in dental plaque
DNA on fossil teeth offers clues to past lifestyles, health and disease. Christina Warinner’s work with microbes hasn’t made her a germaphobe. “It’s given me this deep appreciation for this microbial world in which we live,” she says. In a pitch-black rainforest with fluttering moths and crawling centipedes, Christina Warinner dug up her first skeleton. Well, technically it was a full skeleton plus two headless ones, all seated and draped in ornate jewelry. To deter looters, she excavated through the night while one teammate held up a light and another killed as many bugs as possible. As Warinner worked, unanswerable questions about the people whose skeletons she was excavating flew through her mind. “There’s only so much you can learn by looking with your own eyes at a skeleton,” she says. “I became increasingly interested in all the things that I could not see — all the stories that these skeletons had to tell that weren’t immediately accessible, but could be accessible through science.” At age 21, Warinner cut her teeth on that incredibly complex sacrificial burial left behind by the Maya in a Belize rainforest. Today, at age 37, the molecular anthropologist scrapes at not-so-pearly whites to investigate similar questions, splitting her time between the University of Oklahoma in Norman and the Max Planck Institute for the Science of Human History in Jena, Germany.

10-4-17 Early farmers may have polluted the sea 4000 years ago
Early farmers may have polluted the sea 4000 years ago
Heavy metals including cadmium and lead are unusually common in sediments from the South China Sea, hinting that run-off from farms was spilling into the ocean 4000 years ago. Humans have been polluting the environment for at least 4000 years. So say scientists who have analysed sediment from the South China Sea – but not everyone is convinced. Several early civilisations hit a crisis point about 4000 years ago. The global climate cooled, and this has been linked to the collapse of the Akkadian Empire in ancient Mesopotamia, the end of the Indus valley civilisation of South Asia and the fall of the Liangzhu culture in what is now eastern China. Cooling was also felt on Hainan island off China’s southern coast, according to Fangjian Xu at the China University of Petroleum, Qinqdao, Bangqi Hu at the Qingdao Institute of Marine Geology, and their colleagues. The cooling led to an increase in heavy metal pollution in the South China Sea. Xu and his colleagues looked at two sediment cores from just south-east of Hainan. They calculated “enrichment factors” for several metals. A value of 1 or below indicates no enrichment, while values between 1 and 3 suggest “minor enrichment”. The enrichment factors of cadmium and lead hovered around 1 before the 4000-year mark, but afterwards increased to about 1.5. In other words, human activity on Hainan 4000 years ago led to a subtle but detectable uptick in heavy metal pollution in the South China Sea, says the team.

10-4-17 New York City mice may be evolving to eat fast food like pizza
New York City mice may be evolving to eat fast food like pizza
White-footed mice from New York City are genetically distinct from their country-dwelling cousins, and their urban diets may be responsible. There are always better restaurants in the city, and that could be making the town mice of New York genetically distinct from their country cousins. Stephen Harris at the State University of New York and Jason Munshi-South of Fordham University in New York City caught 48 white-footed mice (Peromyscus leucopus) from three New York parks and three nearby rural areas. The mice are native to this part of North America, so the pair wanted to find out whether some had begun to evolve for city living. They examined the mice’s RNA to see if the rural and urban populations expressed different genes. Ultimately, they homed in on 19 single nucleotide polymorphisms (SNPs): places in the genome where a single letter varies from mouse to mouse. Several SNPs were in genes associated with digestion and other metabolic processes. One highlighted gene was used to produce omega-3 and omega-6 fatty acids. A version of this gene appears to have been selected for in humans as we moved from hunter-gathering to agriculture.

10-4-17 WHO launches bold plan to slash cholera deaths by 90 per cent
WHO launches bold plan to slash cholera deaths by 90 per cent
The global health agency pledged to reduce the death toll – now running at 95,000 a year – by improving sanitation and strategically deploying an oral vaccine. The World Health Organization and 50 other agencies working on health and international development have declared war on cholera. A road map will be launched today that describes how the partners plan to cut deaths from the water-borne bacteria – now running at 95,000 a year – by 90 per cent by 2030. That will mean eliminating cholera from 20 of the 47 countries that have it, and enabling the rest to detect and stop outbreaks before they get out of control, according to this Global Task Force on Cholera Control. The challenge is daunting. Three million people get cholera every year, in Asia, Africa and Haiti, and increasing urbanisation and temperatures will put more people at risk. In Yemen, the biggest epidemic in modern times is now approaching 800,000 cases, and is growing. Emergency experts say a “catastrophic” outbreak looms in Rohingya refugee camps in Bangladesh. We already have the tools to stop this, says Peter Salama, head of emergency operations at the WHO in Geneva, Switzerland. Cholera spreads in water containing infected faeces. Rich countries banished it a century ago, not with vaccines, but with toilets and hygiene. In poor countries, 2 billion people drink from water sources contaminated with faeces and 2.4 billion have no toilets, according to the WHO. Yet aid from rich countries to build sewage systems has fallen.

10-3-17 First global pledge to end cholera by 2030
First global pledge to end cholera by 2030
Health officials from around the world are meeting in France to commit to preventing 90% of cholera deaths by 2030. The disease, which is spread through contaminated water, kills about 100,000 people every year. It is the first time governments, the World Health Organization, aid agencies and donors have made such a pledge. It comes as Yemen continues to fight one of the worst cholera outbreaks on record. Cholera has been spreading in the war-torn country due to deteriorating hygiene and sanitation conditions and disruptions to the water supply. More than 770,000 people have been infected with the disease, which is easily treatable with the right medical equipment, and 2,000 have died. Many of the victims are children. These huge outbreaks tend to grab the headlines, but there are also frequent outbreaks in so-called cholera "hotspots". Cholera is an acute diarrhoeal infection caused by ingestion of food or water contaminated with the bacterium Vibrio cholera. It can spread quickly and widely in cramped, dirty conditions. The infection is cheap to treat with rehydration salts, and easy to avoid altogether if people have access to clean water and decent toilet facilities. But about two billion people globally lack access to clean water and are potentially at risk of cholera, according to the World Health Organization. The UN health agency says weak health systems, and outbreaks not being detected early enough also contribute to the rapid spread of outbreaks.

10-3-17 Six in seven contact lens wearers take unnecessary risks with their eyes
Six in seven contact lens wearers take unnecessary risks with their eyes
Rinsing or storing lenses in tap water is not a good idea. Contact lens wearers can be lax about practicing good hygiene habits, according to a new survey. In some cases, the risky behaviors can lead to eye infections. People in the United States who wear contact lenses share an eye-opening characteristic. Roughly 85 percent report regularly taking at least one risk when wearing or cleaning their lenses. In the Aug. 18 Morbidity and Mortality Weekly Report, researchers at the U.S. Centers for Disease Control and Prevention describe results from a 2016 national survey of more than 6,000 people. Contrary to previous studies, teens did better in some categories than adults. The no-no’s below can lead to serious eye infections, mainly by introducing microorganisms into the eye. Even water that’s safe to drink or swim in can bug up lenses.

10-3-17 The rise of agricultural states came at a big cost, a new book argues
The rise of agricultural states came at a big cost, a new book argues
Mobile groups traded health and happiness for settled societies. Early agricultural states that formed in Egypt and elsewhere were fragile creations, not least because of crowding, epidemics, droughts and popular resistance to taxation and conscription into armies, contends political anthropologist James C. Scott in his new book. Contrary to popular opinion, humans didn’t shed a harsh existence as hunter-gatherers and herders for the good life of stay-in-place farming. Year-round farming villages and early agricultural states, such as those that cropped up in Mesopotamia, exchanged mobile groups’ healthy lifestyles for the back-breaking drudgery of cultivating crops, exposure to infectious diseases, inadequate diets, taxes and conscription into armies. In Against the Grain, political anthropologist James C. Scott offers a disturbing but enlightening defense of that position. He draws on past and recent archaeological studies indicating that the emergence of state-run societies around 6,000 years ago represented a cultural step backward in some important ways. Scott has previously written about modern states’ failed social engineering projects and the evasion of state control by present-day mountain peoples in Southeast Asia. Exploring the roots of state-building was a logical next step. Neither agriculture nor large settlements, on their own, stimulated state formation, Scott argues. Middle Eastern foragers cultivated grains thousands of years before year-round villages appeared. Large, permanent settlements depending substantially on wild plants and marine food materialized in Mesopotamia well before agricultural states formed there.

10-3-17 A baby ichthyosaur’s last meal revealed
A baby ichthyosaur’s last meal revealed
Baby ichthyosaurs may have noshed on squid, a new analysis of a museum fossil suggests. As far as last meals go, squid isn’t a bad choice. Cephalopod remains appear to dominate the stomach contents of a newly analyzed ichthyosaur fossil from nearly 200 million years ago. The ancient marine reptiles once roamed Jurassic seas and commonly pop up in England’s fossil-rich coast near Lyme Regis. But a lot of ichthyosaur museum specimens lack records of where they came from, making their age difficult to place. Dean Lomax of the University of Manchester and his colleagues reexamined one such fossil. Based on its skull, they identified the creature as a newborn Ichthyosaurus communis. Microfossils of shrimp and amoeba species around the ichthyosaur put the specimen at 199 to 196 million years old, the researchers estimate. Tiny hook structures stand out in the newborn’s ribs — most likely the remnants of prehistoric black squid arms. Another baby ichthyosaur fossil that lived more recently had a stomach full of fish scales. So the new find suggests a shift in the menu for young ichthyosaurs at some point in their evolutionary history, the researchers write October 3 in Historical Biology.

10-3-17 Prehistoric reptile's last meal revealed
Prehistoric reptile's last meal revealed
The fossil of a marine reptile that lived 199 million years ago has been identified as a newborn that ate squid as its last meal. The reptile was an ichthyosaur, which gave birth to live young. It belongs to the group Ichthyosaurus communis, which was the first species of ichthyosaur to be recognised by science in 1821. The "exceptional" specimen is the first juvenile of its species to be identified, say researchers. The reptile had remnants of squid inside its stomach when it died. "Many tiny hook-like structures are preserved between the ribs," said Dean Lomax of the University of Manchester, UK. "These are from the arms of prehistoric squid. So, we know this animal's last meal before it died was squid." Ichthyosaurs occupy a special place in the history of fossil collecting in the UK.

10-2-17 Life may have begun millions of years earlier than we thought
Life may have begun millions of years earlier than we thought
Two major studies argue that life arose on Earth very soon after it formed, but both have already come in for heavy criticism. Life may have begun on our planet hundreds of millions of years earlier than thought, according to two studies published this week. But both papers are already proving controversial. Ben Pearce of McMaster University in Hamilton, Ontario, Canada, and colleagues simulated conditions on early Earth to find out how readily the key molecules of life could have formed. They focused on “warm little ponds” on land, which are one of the suspected sites of the origin of life – the other being deep-sea vents. Pearce tackled the formation of RNA, a close cousin of DNA that is widely thought to have been the basis for the first life. Many of the building blocks of RNA are found in asteroids and meteoroids, so Pearce calculated how much could have been delivered to Earth by impacting rocks – of which there were plenty during Earth’s first billion years – and then how much could have accumulated in ponds, given the molecules’ fragility and tendency to leech away. He concluded that RNA could have formed within a handful of years of major impacts, implying that life could have formed very early in Earth’s history. There are two problems with this argument, says John Sutherland of the MRC Laboratory of Molecular Biology in Cambridge, UK.

10-2-17 Body clock mechanics wins U.S. trio the Nobel Prize in physiology or medicine
Body clock mechanics wins U.S. trio the Nobel Prize in physiology or medicine
Three Americans have won the Nobel Prize in physiology or medicine for discovering the gears of circadian clocks and how they govern daily rhythms, such as sleep, metabolism and other body processes. Discoveries about the clocklike ups and downs of daily life have won Jeffery C. Hall, Michael Rosbash and Michael W. Young the Nobel Prize in physiology or medicine. Circadian rhythms are daily cycles of hormones, gene activity and other biological processes that govern sleep, body temperature and metabolism. When thrown out of whack, there can be serious health consequences, including increased risk of diabetes, heart and Alzheimer’s diseases. Hall and Rosbash discovered the first molecular gear of the circadian clockworks: A protein called Period increases and decreases in abundance on a regular cycle during the day. Young discovered that another protein called Timeless works with Period to drive the clock. Young also discovered other circadian clockworks.

Body Clock and Circadian Rhythms

10-2-17 Medicine Nobel for scientists who unpicked our body clocks
Medicine Nobel for scientists who unpicked our body clocks
Scientists who uncovered how genes build cellular body clocks and keep a 24-hour rhythm have been awarded this year’s Nobel Prize in Physiology or Medicine. The 2017 Nobel Prize in Physiology or Medicine has been awarded jointly to Jeffrey C Hall, Michael Rosbash and Michael W Young for their work on the mechanisms controlling circadian rhythms – the internal clocks that living organisms use to track the day-night cycle. All life on Earth has evolved on a planet that spins on its axis once every 24 hours. As different parts of its surface face the sun, conditions can change dramatically. Days bring warmth and light, nights are cool and dark. A biological clock in the cells of plants, animals and humans anticipates these fluctuations to optimise behaviour and physiology. The existence of an inner clock has been known about since 1729 when French scientist Jean-Jaques d’Ortous de Mairan found that the daily movement of a plant’s leaves to track the sun continued when it was kept in the dark. There must be something inside plants controlling the daily progression. But what that was remained a mystery for a long time. To find out, this year’s Nobel laureates looked inside the cells of fruit flies to see how they ticked. In 1984 they studied a gene called period. Hall and Rosbach found that it acts like an hour glass, producing a protein that accumulates in the cell during the night and then degrades during the day. They then found that this ebb and flow is controlled by the period protein itself, which inhibits the activity of the gene that makes it. As levels increase, production stops. The same gene was found to be at work in other organisms too, including humans.

10-2-17 Body clock scientists win Nobel Prize
Body clock scientists win Nobel Prize
Three scientists who unravelled how our bodies tell time have won the 2017 Nobel Prize for physiology or medicine. The body clock - or circadian rhythm - is the reason we want to sleep at night, but it also drives huge changes in behaviour and body function. The US scientists Jeffrey Hall, Michael Rosbash and Michael Young will share the prize. The Nobel prize committee said their findings had "vast implications for our health and wellbeing". A clock ticks in nearly every cell of the human body, as well as in plants, animals and fungi. Our mood, hormone levels, body temperature and metabolism all fluctuate in a daily rhythm. Even our risk of a heart attack soars every morning as our body gets the engine running to start a new day. The body clock so precisely controls our body to match day and night that disrupting it can have profound implications. The ghastly experience of jet lag is caused by the body being out of sync with the world around it. In the short term, body clock disruption affects memory formation, but in the long term it increases the risk of diseases, including type 2 diabetes, cancer and heart disease.

10-2-17 We’re nearly ready to use CRISPR to target far more diseases
We’re nearly ready to use CRISPR to target far more diseases
Forget editing embryos. We’re nearly ready to use CRISPR to change DNA inside our own bodies to treat many disorders, from hepatitis B to muscular dystrophy. The race is on to edit the DNA in our body to fight or prevent disease. Promising results from animal studies targeting the liver, muscles and the brain suggest that the CRISPR genome-editing method could revolutionise medicine, allowing us to treat or even cure a huge range of disorders. The CRISPR genome-editing method was only developed in 2012, but it is proving so powerful and effective that around 20 trials in humans have already begun or will soon. Almost all of these involve removing cells from an individual’s body, editing their DNA and then putting them back into the body. This approach has immense promise, for instance, it is being used to alter immune cells to make them better at killing cancers. It’s relatively easy to remove immune cells or blood stem cells, edit them, and then return them to the body, but this isn’t possible with most bodily tissues. So editing cells inside the body would allow us to treat far more conditions – from genetic disorders to high cholesterol – and would also be cheaper than growing and editing cells outside the body. What diseases could be treated this way? “Absolutely everything,” says Irina Conboy of the University of California, Berkeley. The big challenge is delivering the CRISPR machinery to tissues inside the body. Editing genes with CRISPR requires at least two components: a protein that cuts DNA and a piece of RNA that guides it to the precise DNA site to make the cut.

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