By JOHN S. SPARKS and CHRISTOPHER B. BRAUN Having departed the surreal landscape of the Ankarana tsingy with our precious collections, we head north to Antsiranana, a large town at the northern tip of Madagascar. Our focus now has shifted to obtaining data related to the evolution of hearing in the endemic Malagasy cichlids. As mentioned in a previous post, these fish have a highly modified gas bladder with elaborate anterior projections that actually enter the skull and come in contact with the inner ear. Any type of sound field will resonate within that air-filled cavity to vibrate, stimulating the ear. We have already shown that such fish have much more sensitive hearing than their relatives. We are trying to determine if there is an environmental correlation that might explain why some species have such sensitive hearing but others do not. Rivers can be very quiet places if they flow over a smooth flat bottom, but if the river bank contains richer three-dimensional structures like root masses or rock formations, the ambient noise can be so loud as to make hearing essentially useless. Most rivers contain both types of habitat, of course, so we’re here to see specifically where the fish are found and what the noise regime is like. Our first target is a species of Ptychochromis that has only been collected once before, and has never been examined alive. We head out over roads that skirt the northwestern flank of Montagne de Ambre (Amber Mountain), although these roads are more akin to boulder strewn canyons that put our 4WD vehicles to the test. After driving for a number of hours through trails barely wide enough for two people walking abreast, we run into mud so deep we are forced to turn back — there is not enough time for us to walk to our destination, so the most northerly cichlid ever collected in Madagascar will have to wait for another time. We are disappointed, but the smell of mud and Zebu excrement mélange is something we don’t mind leaving behind. © 2011 The New York Times Company

Keyword: Hearing; Evolution
Link ID: 15449 - Posted: 06.18.2011

By Susan Gaidos Video games can be mesmerizing, even for a rhesus monkey. Which may explain, in part, why 6-year-old Jasper has been sitting transfixed at a computer screen in a Washington University lab for nearly an hour, his gaze trained on a small red ball. A more interesting reason for Jasper’s quiet demeanor is that he is hurling the ball at a moving target using just his thoughts. Jasper is not the only monkey to control objects with his mind. At the University of Pittsburgh, a pair of macaques manipulated a thought-controlled synthetic arm to grab and eat marsh­mallows. The monkeys then worked the arm to turn a doorknob — no muscle power required. In another case, a monkey in North Carolina transmitted its thoughts halfway around the world to set a Japanese robot in motion. Now it’s time to let humans give it a serious try. In a series of clinical trials, scientists are preparing to take thought-controlled technologies, known as brain-computer interfaces, to those who might benefit most. The trials are a major step in realizing what many scientists say is an ambitious, but fully obtainable, goal — to restore mobility and independence to people who have lost the use of their muscles through brain or spinal cord injury. Over the next few years, paralyzed patients will attempt to learn how to maneuver virtual hands and robotic arms to reach, push, grasp or eat. As the trials progress, researchers hope to train users to perform increasingly complex movements. © Society for Science & the Public 2000 - 2011

Keyword: Robotics
Link ID: 15448 - Posted: 06.18.2011

By BENEDICT CAREY Scientists have designed a brain implant that restored lost memory function and strengthened recall of new information in laboratory rats — a crucial first step in the development of so-called neuroprosthetic devices to repair deficits from dementia, stroke and other brain injuries in humans. Though still a long way from being tested in humans, the implant demonstrates for the first time that a cognitive function can be improved with a device that mimics the firing patterns of neurons. In recent years neuroscientists have developed implants that allow paralyzed people to move prosthetic limbs or a computer cursor, using their thoughts to activate the machines. In the new work, being published Friday, researchers at Wake Forest University and the University of Southern California used some of the same techniques to read neural activity. But they translated those signals internally, to improve brain function rather than to activate outside appendages. “It’s technically very impressive to pull something like this off, given our current level of technology,” said Daryl Kipke, a professor of bioengineering at the University of Michigan who was not involved in the experiment. “We are just scratching the surface when it comes to interacting with the brain, but this experiment shows what’s possible and the great potential of interacting with the brain in this way.” In a series of experiments, scientists at Wake Forest led by Sam A. Deadwyler trained rats to remember which of two identical levers to press to receive water; the animals first saw one of the two levers appear and then (after being distracted) had to remember to press the other lever to be rewarded. Repeated training on this task teaches rats the general rule, but in each trial the animal has to remember which lever appeared first, to inform the later choice. © 2011 The New York Times Company

Keyword: Learning & Memory
Link ID: 15447 - Posted: 06.18.2011

By PAMELA PAUL It’s no shock that we can’t tell what the Botoxed are feeling. But it turns out that people with frozen faces have little idea what we’re feeling, either. No, Botox injections don’t zap brain cells. (At least not so far as we know.) According to a new study by David T. Neal, an assistant professor of psychology at the University of Southern California, and Tanya L. Chartrand, a professor of marketing and psychology at the Duke University Fuqua School of Business, people who have had Botox injections are physically unable to mimic emotions of others. This failure to mirror the faces of those they are watching or talking to robs them of the ability to understand what people are feeling, the study says. The idea for the paper stemmed from a study conducted in the 1980s, which found that long-married men and women began to resemble each other over time, especially if they were happily wed. “So we thought, what’s going to happen now that there’s Botox?” Dr. Neal said. The toxin might interfere with “embodied cognition,” the way in which facial feedback helps people perceive emotion. According to the theory in the study, a listener unconsciously imitates another person’s expression. This mimicry then generates a signal from the person’s face to his or her brain. Finally, the signal enables the listener to understand the other person’s meaning or intention. While the first two steps of this process had been established by research, it was unclear whether facial feedback helped people make better judgments about other peoples’ emotions. © 2011 The New York Times Company

Keyword: Emotions
Link ID: 15446 - Posted: 06.18.2011

By ROBBIE BROWN ELKMONT, Tenn. — Lynn Faust remembers the old days of firefly season here. You would hike into the woods at night, with nobody else around, waiting for one of nature’s strangest and most beautiful rituals. Then the fireflies would emerge, thousands and thousands of them, and under the moonlight they would all flash in unison. On. Off. On. Off. “It’s as though they wear little watches,” said Ms. Faust, 56, a biologist and naturalist who has studied fireflies for decades. “It’s awe-inspiring, it’s beautiful, it’s rhythmic and it’s bright. You’re surrounded by the fireflies.” These days, you are also surrounded by the tourists. The secret is out about this marvelously rare and very brief annual spectacle. About a thousand tourists a night come to Elkmont, a small trailhead in Great Smoky Mountains National Park, during the two weeks each June when the country’s largest population of synchronous fireflies puts on what locals call “the light show.” Reactions tend toward the spiritual, and people wander out of the woods with the quiet, dazed look of those who have seen aurora borealis or a solar eclipse, or spent an hour getting massaged at Sedona. “It’s mind-blowing, like a silent symphony,” said Daniel Carlson, 47, an engineer from Raleigh, N.C., lying flat on a blanket in the forest. “How? Why? Why here? We have no clue.” © 2011 The New York Times Company

Keyword: Sexual Behavior
Link ID: 15445 - Posted: 06.16.2011

By SHARON LaFRANIERE MENGXI VILLAGE, China — On a chilly evening early last month, a mob of more than 200 people gathered in this tiny eastern China village at the entrance to the Zhejiang Haijiu Battery Factory, a maker of lead-acid batteries for motorcycles and electric bikes. They shouldered through an outer brick wall, swept into the factory office and, in an outpouring of pure fury, smashed the cabinets, desks and computers inside. News had spread that workers and villagers had been poisoned by lead emissions from the factory, which had operated for six years despite flagrant environmental violations. But the truth was even worse: 233 adults and 99 children were ultimately found to have concentrations of lead in their blood, up to seven times the level deemed safe by the Chinese government. One of them was 3-year-old Han Tiantian, who lived just across the road from the plant. Her father, Han Zongyuan, a factory worker, said he learned in March that she had absorbed enough lead to irreversibly diminish her intellectual capacity and harm her nervous system. “At the moment I heard the doctor say that, my heart was shattered,” Mr. Han said in an interview last week. “We wanted this child to have everything. That’s why we worked this hard. That’s why we poisoned ourselves at this factory. Now it turns out the child is poisoned too. I have no words to describe how I feel.” Such scenes of heartbreak and anger have been repeated across China in recent months with the discovery of case after case of mass lead poisoning — together with instances in which local governments tried to cover them up. © 2011 The New York Times Company

Keyword: Neurotoxins; Development of the Brain
Link ID: 15444 - Posted: 06.16.2011

By ABBY GOODNOUGH and KATIE ZEZIMA BROCKTON, Mass. — Michael Capece had been snorting OxyContin for five years when a new version of the drug, intended to deter such abuse, hit the market last summer. The reformulated pills are harder to crush, turning instead into a gummy substance that cannot be easily snorted, injected or chewed. Instructed by his dealer, Mr. Capece, 21, tried microwaving one of the new pills, then sniffing up the burnt remains. Other addicts have tried to defeat the new formula by freezing, baking or soaking the pills in solvents ranging from soda to acetone. Many are ending up frustrated. “It’s too much work,” said Mr. Capece who entered a rehab program here last month. “It wasn’t anything I enjoyed.” A powerful narcotic meant for cancer patients and others with searing pain, OxyContin is designed to slowly release its active ingredient, oxycodone, over 12 hours. But after it was introduced in 1996, drug abusers quickly discovered that chewing an OxyContin tablet — or crushing one and snorting the powder, or injecting it with a needle — produced an instant high as powerful as heroin. It has been blamed for waves of addiction that have ravaged certain regions of the country, and has been a factor in many overdose deaths. © 2011 The New York Times Company

Keyword: Drug Abuse
Link ID: 15443 - Posted: 06.16.2011

Sandrine Ceurstemont, video producer How does an octopus locate a hidden meal? In this video, filmed by Michael Kuba and his team at the Hebrew University of Jerusalem, food is placed in one compartment of a maze denoted with a visual cue. The octopus picks the right route and successfully retrieves the treat. It's the first time that an octopus has been shown to guide one of its arms to a location, based on sensory input, using a complex movement. In the wild, octopuses use their arms to search for food in small crevices. Previously, it's been thought that they feel their way to a food source by simply using sensors on their tentacles. Now this research is showing that they are capable of more complex processing, in this case by combining information from their tentacles with visual input to achieve a goal. Six out of the seven octopuses tested successfully learned the task and used the strategy more often once it was mastered. It's only one example of clever tricks used by cephalopods. Check out our full-length feature to find out more about these animals' astounding mental skills. © Copyright Reed Business Information Ltd.

Keyword: Intelligence; Evolution
Link ID: 15442 - Posted: 06.16.2011

by Mark Cohen My medical assistant put the chart on my desk. “your next patient is in room five, Dr. Cohen. Her name is Taylor and 
she’s a cutie!” “Thanks, Mary,” I said, pulling up Taylor’s medical record on my desktop computer. I glanced at the consultation request: Six-year-old girl with speech problem. As a developmental pediatrician, I am often called on to evaluate children’s speech and language. Those are among the most complex tasks the young brain has to master, so it’s no wonder many childhood disorders express themselves in those areas. Kids with developmental delay or autism commonly show up in the pediatrician’s office with a parent who simply says, “My child isn’t talking.” When I opened the door to the examining room, I saw a petite girl with long, blond hair sitting very still on the exam table. She wore a purple jumper over a short-sleeved white blouse, and her hair was tied at the back with a ribbon that matched her dress. She was deeply engrossed in reading a Dr. Seuss book. She looked up at me and smiled. “Hi,” I said. “I’m Dr. Cohen. What’s your name?” The girl continued to smile, but she didn’t say anything and quickly went back to her reading. Hmmm. Could just be a shy one, I thought. I turned to her mother. “I understand your daughter is having some problems with her speech. Can you tell me what your concerns are?” © 2011, Kalmbach Publishing Co.

Keyword: Language; Development of the Brain
Link ID: 15441 - Posted: 06.16.2011

Meredith Wadman The unusual meeting was held in a conference room, but it might have been called a war room. Gathered inside a little-known research centre in southern Louisiana, the people who oversee chimpanzee research in the United States were preparing to battle for the survival of their enterprise. Although no other country besides Gabon carries out invasive experiments with chimpanzees, the United States continues such work at three major research facilities. Louisiana's New Iberia Research Center (NIRC) is the largest, with a population of 360 chimps, used by investigators from pharmaceutical companies and federal agencies to test new drugs and study diseases such as hepatitis. During the meeting, Thomas Rowell, director of the NIRC, stood up, surveyed the audience, and launched into a presentation about possible strategies to build public support for their work. Another slide went on to note that the National Institutes of Health (NIH) spends about US$12 million a year caring for the chimpanzees it supports (currently totalling 734), versus the billions in health-care costs for the human diseases that can be studied through experiments on chimpanzees. One of them, hepatitis C, currently affects at least 170 million people globally. If researchers don't have access to the chimp model, said Rowell, people afflicted with hepatitis C will suffer. "Their lifespans are going to be shortened. They will not have a proper quality of life." He called them a "silent voice". © 2011 Nature Publishing Group,

Keyword: Animal Rights
Link ID: 15440 - Posted: 06.16.2011

By Mark Schaller We are prejudiced against all kinds of other people, based on superficial physical features: We react negatively to facial disfigurement; we avoid sitting next to people who are obese, or old, or in a wheelchair; we favor familiar folks over folks that are foreign. If I asked you why these prejudices exist and what one can do to eliminate them, your answer probably wouldn't involve the words "infectious disease." Perhaps it should. What does infectious disease have to do with these prejudices? The answer lies in something that I've come to call the "behavioral immune system." The behavioral immune system is our brain's way of engaging in a kind of preventative medicine. It's a suite of psychological mechanisms designed to detect the presence of disease-causing parasites in our immediate environment, and to respond to those things in ways that help us to avoid contact with them. This has many important implications – for prejudice, for sexual attraction, for social interaction, and even for the origins of cultural differences. (And, yes, for health too.) It makes immediate sense that people would develop aversions against people who actually have infectious diseases. But why does it also lead to these aversions to perfectly healthy people? Because it's impossible to directly detect the presence of bacteria and viruses and other microscopic parasites; and so we're forced to use crude superficial cues. Consequently, we make mistakes. Some of those mistakes lead to the irrational avoidance of things (including people) that pose no infection risk at all. © 2011 Scientific American

Keyword: Emotions; Neuroimmunology
Link ID: 15439 - Posted: 06.16.2011

Peter Dejong The hallucinogen found in "magic mushrooms" could help treat a variety of psychiatric disorders, including depression, anxiety and even addiction, researchers say. A new study provides clues on how much of the substance patients could take to get the greatest benefit with the least risk, researchers say. However, use of the substance, called psilocybin, is not without risk. Its side effects include paranoia and delusions. Under the second-highest dose given in the study, patients said they had a "mystical" experience that they felt was significantly personal and spiritual, but few noted any side effects. Participants reported improvements in attitude, mood and behavior that were confirmed by their friends and family. The study was small and much more research is needed to determine exactly how it's working. And even if the drug becomes available for prescription, it should always be given under the supervision of properly trained personnel, the researchers said. "The model of it would never be, 'take two of these and call me in the morning,'" said study researcher Matthew Johnson, an assistant professor of psychiatry and behavioral sciences at Johns Hopkins University. "Someone having an adverse reaction might be so scared they might run across a highway and be hit by a car," he said. "We wouldn't encourage anyone to do these things in a non-supervised context." © 2011 msnbc.com

Keyword: Drug Abuse
Link ID: 15438 - Posted: 06.16.2011

There are potential risks to babies born to women who took antipsychotic drugs in pregnancy, Health Canada says. The department said it is updating safety information on the drug labels to highlight the potential risk of abnormal muscle movements and withdrawal symptoms in newborns whose mothers were treated with the drugs during the third trimester. Babies born to women treated with antipsychotic drugs during the third trimester run the risk of abnormal muscle movements and withdrawal symptoms, Health Canada says.Babies born to women treated with antipsychotic drugs during the third trimester run the risk of abnormal muscle movements and withdrawal symptoms, Health Canada says. Michaela Rehle/Reuters Antipsychotic drugs are used to treat symptoms of psychiatric disorders such as schizophrenia and bipolar disorder. Health Canada said it has notified Canadian manufacturers of typical and newer antipsychotic drugs to update safety labels. "Women taking an antipsychotic and who are pregnant or thinking of becoming pregnant should talk to their doctor about their treatment," Health Canada advised in a statement Wednesday. "Patients should not stop taking their medication without first speaking to a healthcare practitioner, as abruptly stopping an antipsychotic drug can cause serious adverse events." © CBC 2011

Keyword: Development of the Brain; Schizophrenia
Link ID: 15437 - Posted: 06.16.2011

by Shaoni Bhattacharya THERE is growing evidence that chronic use of the recreational drug ketamine is linked with severe bladder problems. The findings may also have implications for the drug's use as an antidepressant. Used safely as a medical anaesthetic and analgesic for decades, ketamine has also risen in popularity as a recreational drug. The first case of severe bladder problems linked with ketamine use was documented in 2007, but little is known about the extent or cause of the problem. Now a group of surgeons and scientists have raised the alarm in a review calling for more investigation (BJU International, DOI: 10.1111/j.1464-410X.2010.10031.x). They highlight effects such as incontinence and bladder shrinkage, as well as damage to the kidneys and ureter in people using ketamine frequently. "It has a major impact on users such that they can be incontinent or have enormous pain," says Dan Wood, a consultant urologist at University College London Hospitals, who led the review. He has seen 20 chronic ketamine users with urinary problems in the last three years and had to remove four patients' bladders. The review suggests that heavy users are more likely to suffer symptoms, and about 20 per cent of people who have taken high doses of ketamine several times a week over months to years have experienced urinary tract problems. © Copyright Reed Business Information Ltd.

Keyword: Drug Abuse
Link ID: 15436 - Posted: 06.16.2011

By Laura Sanders The anesthetic ketamine works against depression by quickly boosting levels of a brain compound that has been linked to the condition, a new study in mice shows. The research may lead to highly effective and fast-acting antidepressants that provide relief within hours instead of weeks, scientists report online June 15 in Nature. Traditional antidepressants can be effective but often take weeks or months to improve symptoms. “You can control malignant hypertension within minutes; a bad increase in blood sugar, bad migraines, asthma attacks, within minutes,” says psychiatrist Carlos Zarate of the National Institute of Mental Health in Bethesda, Md. “Yet why in psychiatry should we be satisfied with, ‘Just hang on for a few weeks or a few months, and you’re going to get better?’ That’s not acceptable in my mind.” The new study may point to faster alternatives, Zarate says: “Here is increasing evidence that you can go more directly at the target, and that’s maybe why you get more of a rapid antidepressant effect.” Mice receiving a single injection of ketamine showed fewer signs of depression just half an hour after the shot, and they continued to show multiple signs of reduced depression for a week, researchers at the University of Texas Southwestern Medical Center at Dallas found. For example, after one dose of ketamine, mice struggled longer to stay afloat in a beaker of water instead of giving up and sinking. © Society for Science & the Public 2000 - 2011

Keyword: Depression; Drug Abuse
Link ID: 15435 - Posted: 06.16.2011

Daniel Gilbert The London Association for the Prevention of Premature Burial was founded in 1896 to prevent “premature burial generally, and especially amongst the members”1. Because nineteenth-century physicians couldn't always distinguish the nearly dead from the really most sincerely dead, premature burial was a problem. But not a big problem. The odds of being buried alive in 1896 were, like the odds of being buried alive today, very close to zero. Nonetheless, the good citizens of England formed action committees, wrote editorials and promoted legislation that ultimately led to expensive safeguards against “the horrible doom of being buried alive”1. Most of those safeguards — such as the costly requirement that bodies spend time in 'attractive waiting mortuaries' before being buried — are still with us today. The frequency with which modern cadavers use this waiting period to demonstrate that they've been misdiagnosed is approximately never. Premature burial isn't a big problem, but the way we deal with big problems is. When an aeroplane's fuselage rips open mid-flight, or an offshore oil rig explodes, or a nuclear power plant is crippled by a tsunami, we immediately ask what could have been done differently, blame those who didn't do it, then allocate funds and pass legislation to make sure it gets done that way the next time. At first blush, this seems sensible. After all, no one is in favour of aviation accidents, reactor meltdowns or oil spills; so when these things happen, why not do everything we can to make sure they don't happen again? The answer is that because resources are finite, every sensible thing we do is another sensible thing we don't. Alas, research shows that when human beings make decisions, they tend to focus on what they are getting and forget about what we are forgoing. For example, people are more likely to buy an item when they are asked to choose between buying and not buying it than when they are asked to choose between buying the item and keeping their money “for other purchases”. © 2011 Nature Publishing Group,

Keyword: Attention; Learning & Memory
Link ID: 15434 - Posted: 06.16.2011

Erika Check Hayden Two years ago, 13-year-old Alexis Beery developed a cough and a breathing problem so severe that her parents placed a baby monitor in her room just to make sure she would survive the night. Alexis would often cough so hard and so long that she would throw up, and had to take daily injections of adrenaline just to keep breathing. Yet doctors weren't sure what was wrong. In a paper published today in Science Translational Medicine1, researchers led by Richard Gibbs, head of the Baylor College of Medicine Human Genome Sequencing Center in Houston, Texas, describe how they sequenced the genomes of Alexis and her twin brother, Noah, to diagnose the cause of her cough — a discovery that led to a treatment. Today, Alexis is playing soccer and running, and her breathing problem has gone, says Alexis's mother, Retta. "We honestly didn't know if Alexis was going to make it through this," Retta Beery says. "Sequencing has brought her life back." At age 5, the Beery twins had already been diagnosed with a genetic disorder called dopa-responsive dystonia, which causes abnormal movements, and had been taking a medication that was apparently successfully treating the condition. When Alexis developed a worsening cough and breathing problem, the twins' neurologists did not think it was related to her dystonia. © 2011 Nature Publishing Group,

Keyword: Genes & Behavior; Movement Disorders
Link ID: 15433 - Posted: 06.16.2011

Jeremy Laurance "Sexual orientation is not a matter of choice, it is primarily neurobiological at birth." So said Jerome Goldstein, director of the San Francisco Clinical Research Centre, addressing 3,000 neurologists from around the world at the 21st meeting of the European Neurological Society (ENS) in Lisbon last month. In doing so he was attempting to settle a debate that has raged for decades: are gays born or made? It is a puzzle because homosexuality poses a biological conundrum. There is no obvious evolutionary advantage to same-sex relationships. So why are some people attracted to others of the same sex? Sexual attraction provides the drive to reproduction – sex is a means to an end not, in Darwinian terms, an end in itself. From an evolutionary perspective, same-sex relationships should be selected out. Despite this, they are common in the animal kingdom. Birds do it, bees probably do it and fleas may do it, too. Among the many examples are penguins, who have been known to form lifelong same-sex bonds, dolphins and bonobos, which are fully bisexual apes. Various explanations have been advanced for the evolutionary advantage that such relationships might confer. For example, female Laysan albatrosses form same-sex pairs, which are more successful at rearing chicks than single females. Homosexuality may also help social bonding or ease conflict among males where there is a shortage of females. Gay couples will not preserve their own genes but they may help preserve those of the group to which they belong. ©independent.co.uk

Keyword: Sexual Behavior
Link ID: 15432 - Posted: 06.14.2011

by Caroline Williams Octopuses' astonishing mental skills might help us unearth the roots of intelligence – but first we need to understand what makes them so smart BETTY the octopus is curled up in her den, eyes half-closed and clutching a piece of red Lego like a child with a teddy bear. She is, says Kerry Perkins, cephalopod researcher at the Sea Life aquarium in Brighton, UK, much better behaved than some of the octopuses she has worked with. One used to short-circuit a light in its tank by squirting water at it, and would do so whenever the bulb was left on at night. Another made a bid for freedom via the aquarium drainage system, which it seemed to know headed straight out to sea. "Any octopus tank worth its salt has a way of stopping the octopus from escaping," Perkins says as she adds two weights to the lid of Betty's tank. "They love to explore." Aristotle once took this kind of curiosity as a sign that octopuses are stupid - after all, he pointed out, just waving your hands in their direction brings them close enough to catch. We now know that it is just one example of how smart they are. Between them, cephalopods, which also include squids, cuttlefish and nautiluses, can navigate a maze, use tools, mimic other species, learn from each other and solve complex problems. If the latest analyses are to be believed, these skills might show a rudimentary form of consciousness. Cephalopods are the only invertebrates that can boast anything like this kind of mental prowess, and some of their more impressive tricks are shared with only the cleverest vertebrates, such as chimps, dolphins and crows. Yet they evolved along a completely separate path, from snail-like ancestors, and their brains look completely alien to our own (see "A brain apart"). © Copyright Reed Business Information Ltd.

Keyword: Evolution; Intelligence
Link ID: 15431 - Posted: 06.14.2011

By Tina Hesman Saey Bad news for fans of the X-Men: It may take longer to create a new class of mutant superhumans than previous estimates suggested. The first direct measurements of human mutation rates reveal that the speed at which successive generations accumulate single-letter genetic changes is much slower than previously thought. The study, published online June 12 in Nature Genetics, also shows that some individuals mutate faster than others. That means it may be fairly common for people to inherit a disproportionate share of mutations from one parent. Researchers from an international collaboration known as the 1000 Genomes Project deciphered the genetic blueprints of six people from two families — a mother, father and child from each — and counted up the mutations inherited by each child. From there, the team calculated the human mutation rate. “We all mutate,” says study coauthor Philip Awadalla, a population geneticist at the University of Montreal. “And the mutation rate can be extraordinarily variable from individual to individual.” Combined with the results of three similar recent studies, the rate indicates that, on average, about one DNA chemical letter in every 85 million gets mutated per generation through copying mistakes made during sperm and egg production. The new rate means each child inherits somewhere in the neighborhood of 30 to 50 new mutations. © Society for Science & the Public 2000 - 2011

Keyword: Evolution; Genes & Behavior
Link ID: 15430 - Posted: 06.14.2011