By Katherine Harmon The troubled path of diet drugs continues to look challenging, especially after a U.S. Food and Drug Administration (FDA) panel recommended Thursday that the agency not approve a new anti-obesity medication—the second of three to come up for evaluation this year. The new drug, called lorcaserin, acts on the brain's serotonin, a neurotransmitter involved in appetite, digestion, memory, mood and other functions. Serotonin also plays a role in the cardiovascular system, and the diet drug fen-phen (fenfluramine and phentermine) was pulled from the market in the 1990s after it was linked to heart valve problems. When given in high doses, the new medication also gave many rats tumors (though human trials have not been linked to increase cancer risk). "In my opinion the potential risks of the medication outweigh the potential benefits," Heidi Connolly, a panel member and professor of medicine at the Mayo Clinic, told Bloomberg News. Other committee members, however, pointed more to a questionable level of efficacy than concerns over safety in their final vote, which was nine to five against approval. "I really didn't have a lot of issues with the risk," Eric Felner, a panel member and pediatric endocrinologist at Emory University, told The New York Times. "I just didn't see it as being that efficacious." The FDA requires new diet drugs to help people lose at least five percent more of their body weight than a placebo. Those on the lorcaserin lost about 3.3 percent more weight than those on the placebo, according to the Times. But the drug did meet another FDA criteria that at least twice as many people taking the medication (versus those on a placebo) lose five percent or more of their weight. © 2010 Scientific American,

Keyword: Obesity
Link ID: 14476 - Posted: 09.21.2010

By CLAUDIA DREIFUS Q. DID CHILDHOOD VIEWING OF THE “FLIPPER” TELEVISION SERIES MAKE YOU WANT TO BECOME A DOLPHIN RESEARCHER? A. No, it was The New York Times! In the 1970s, I was working as a set designer for an avant-garde theater company in Philadelphia. One Sunday, I read The Times and saw this photograph of a baby whale being killed. Something in me just snapped. “It’s a shame we’re slaughtering these animals when we know so little about them,” I said. I then got a Ph.D. I’ve been devoting myself to studying the abilities and the behaviors of whales and dolphins since. Q. DOLPHINS SPEND MUCH OF THEIR LIVES UNDERWATER. HOW CAN YOU OBSERVE THEIR BEHAVIOR? A. Well, I observe captive dolphins in aquariums. At the moment, my laboratory is an underwater glass booth in the dolphin pool at the National Aquarium in Baltimore. I climb into it with a video camera. The animals are used to me. My goal is to understand their behaviors well enough so that I can find ways to help them tell us about their cognitive capacities. Dolphins, they have these really large, complex brains. The question is: what are they doing with them? These animals look like fish, but the behavior patterns are more like primates and elephants. They are vocal learners, like parrots and humans. What do the sounds they make mean? Copyright 2010 The New York Times Company

Keyword: Intelligence; Evolution
Link ID: 14475 - Posted: 09.21.2010

By JAMES GORMAN Late summer is chili harvest time, when the entire state of New Mexico savors the perfume of roasting chilies, and across the country the delightful, painful fruit of plants of the genus Capsicum are being turned into salsa, hot sauce and grizzly bear repellant. Festivals abound, often featuring chili pepper-eating contests. “It’s fun,” as one chili pepper expert wrote, “sorta like a night out to watch someone being burned at the stake.” In my kitchen, as I turn my homegrown habaneros into hot sauce while wearing a respirator (I’m not kidding) I have my own small celebration of the evolutionary serendipity that has allowed pain-loving humans to enjoy such tasty pain. Some experts argue that we like chilies because they are good for us. They can help lower blood pressure, may have some antimicrobial effects, and they increase salivation, which is good if you eat a boring diet based on one bland staple crop like corn or rice. The pain of chilies can even kill other pain, a concept supported by recent research. Others, notably Dr. Paul Rozin at the University of Pennsylvania, argue that the beneficial effects are too small to explain the great human love of chili-spiced food. “I don’t think they have anything to with why people eat and like it,” he said in an interview. Dr. Rozin, who studies other human emotions and likes and dislikes (“I am the father of disgust in psychology,” he says) thinks that we’re in it for the pain. “This is a theory,” he emphasizes. “I don’t know that this is true.” Copyright 2010 The New York Times Company

Keyword: Pain & Touch; Emotions
Link ID: 14474 - Posted: 09.21.2010

By CARL ZIMMER One day in 2007, Dr. Giulio Tononi lay on a hospital stretcher as an anesthesiologist prepared him for surgery. For Dr. Tononi, it was a moment of intellectual exhilaration. He is a distinguished chair in consciousness science at the University of Wisconsin, and for much of his life he has been developing a theory of consciousness. Lying in the hospital, Dr. Tononi finally had a chance to become his own experiment. The anesthesiologist was preparing to give Dr. Tononi one drug to render him unconscious, and another one to block muscle movements. Dr. Tononi suggested the anesthesiologist first tie a band around his arm to keep out the muscle-blocking drug. The anesthesiologist could then ask Dr. Tononi to lift his finger from time to time, so they could mark the moment he lost awareness. The anesthesiologist did not share Dr. Tononi’s excitement. “He could not have been less interested,” Dr. Tononi recalled. “He just said, ‘Yes, yes, yes,’ and put me to sleep. He was thinking, ‘This guy must be out of his mind.’ ” Dr. Tononi was not offended. Consciousness has long been the province of philosophers, and most doctors steer clear of their abstract speculations. After all, debating the finer points of what it is like to be a brain floating in a vat does not tell you how much anesthetic to give a patient. But Dr. Tononi’s theory is, potentially, very different. He and his colleagues are translating the poetry of our conscious experiences into the precise language of mathematics. To do so, they are adapting information theory, a branch of science originally applied to computers and telecommunications. If Dr. Tononi is right, he and his colleagues may be able to build a “consciousness meter” that doctors can use to measure consciousness as easily as they measure blood pressure and body temperature. Perhaps then his anesthesiologist will become interested. Copyright 2010 The New York Times Company

Keyword: Attention
Link ID: 14473 - Posted: 09.21.2010

by Evelyn Fox Keller ONE of the most striking features of the nature/nurture debate, the argument over the relative roles of genes and environment in human nature, is the frequency with which we read it has been resolved (the answer is neither nature nor nurture, but both) while at the same time we see the debate refuses to die. So what is it that evokes such contradictory claims, that persists in confounding us? Indeed, what is the debate really about? This turns out to be far from easy to explain because different kinds of questions take refuge under its umbrella. Some express concerns that can be addressed scientifically, others may be legitimate and meaningful but perhaps not answerable, and still others make no sense. One reason for the persistence of the nature/nurture debate, then, is that these questions are knitted together by ambiguity and uncertainty into an indissoluble tangle, making it all but impossible to stay focused on a single, well-defined, meaningful question. Another important issue is that some of that ambiguity and uncertainty comes from the language of genetics itself. For example, we may read that the debate is about sorting contributions of nature from those of nurture, and trying to estimate the relative importance, but what exactly is meant by "nature" and "nurture"? Sometimes the distinction is between what is inborn and what is acquired after birth; more often, it is between genes and environment. But not only does nurture affect prenatal development, we also need to ask what exactly is a gene, and what does it do? What do we mean by environment? Does it refer to factors beyond the organism that affect its development, to the milieu in which the fertilised egg develops, or to everything other than the DNA sequence? © Copyright Reed Business Information Ltd.

Keyword: Development of the Brain; Genes & Behavior
Link ID: 14472 - Posted: 09.21.2010

by Anna Reisman Your admission is Evelyn Warwick, little old lady in distress.” The emergency room resident motioned toward a curtained area at the far end of the ward. “Completely delirious.” “Got it,” I said. At the time I was a medical resident at a New York City public hospital, supervising an intern and a medical student. I knew that delirium, an acute confusional state, could result from just about any type of acute illness, or it could be a side effect of medication. And yet, I explained to my team, you could often guess the cause simply from the type of patient. We all agreed about Mrs. Warwick’s probable diagnosis. An elderly woman with delirium at a public city hospital was likely to be a nursing home patient with pneumonia or a urinary tract infection. She might be dehydrated, or maybe she’d had a stroke or a heart attack. When I pulled back the curtain, I did a double take. Evelyn Warwick was a handsome woman with a neat gray bob like an elementary school principal, not a typical city hospital patient. Her pink pajamas glowed against the starched white sheets. Mr. Warwick, a silver-haired man in a tweed jacket, stroked her forehead with a damp cloth. I introduced myself and the team and asked how she was feeling. She opened her watery blue eyes and stared far into the distance. “I don’t know where I am!” she murmured in a clipped British accent. “I woke up and my head exploded.” She looked around the room in a panic and started to weep. “Where am I? What’s all this?” © 2010, Kalmbach Publishing Co.

Keyword: Drug Abuse; Learning & Memory
Link ID: 14471 - Posted: 09.21.2010

By Jennifer Viegas Individual insects and bugs may all look alike to human eyes, but each and every one is unique and possesses its own personality, suggests new research that also helps to explain how personality arises in virtually all organisms. Some individual bugs, like humans, turn out to be shy, while others are very forceful, determined the study, published in the latest Proceedings of the Royal Society B. "Boldness, explorativeness, activity and aggressiveness are the main personality traits usually measured because these connect to each other and appear together," lead author Eniko Gyuris told Discovery News. What makes a bug bold or shy? Gyuris explains the traits manifest themselves a bit differently in insects. "Boldness -- whether they are shier or braver -- could be defined, for example, as to how quickly they start after an alarm, or how soon they come out of their refuge," added Gyuris, a member of the Behavioral Ecology Research Group at the University of Debrecen. "Explorativeness could be measured in another context, namely in which they have the opportunity to discover a new environment with novel objects." Gyuris and his team conducted personality tests on short-winged and long-winged firebugs, a common insect that's known for its striking red and black coloration. The researchers collected these bugs from wild populations in Debrecen, Hungary, and put them through a barrage of different situations. © 2010 Discovery Communications, LLC.

Keyword: Emotions; Evolution
Link ID: 14470 - Posted: 09.21.2010

A virus which causes respiratory infections has been linked to childhood obesity, in a study that is likely to reignite a controversial debate. Previous animal research has implicated common viruses in weight gain, but the evidence has been disputed. The latest study, in Pediatrics, found that obese children with antibodies specific to a certain virus weighed 35lbs (15.8kg) more than those without. Nothing has yet been proven on this theory, say UK experts. Previous research has shown that chicken or mice injected with similar types of viruses showed a statistically significant weight gain. A link between the AD36 virus (adenovirus 36) and obesity in human adults has also been written about previously. But how AD36 infects people and why it affects people differently is still not known. In the University of California study of 124 children aged eight to 18, half of the children were considered obese based on their Body Mass Index. The researchers found the AD36 antibodies in 19 of the children, 15 of whom were in the obese group. Within the group of obese children studied, those with evidence of AD36 infection weighed an average of 35lbs more than obese children who were AD36-negative, says the study. Jeffrey Schwimmer, lead researcher and professor of clinical paediatrics at the University of California school of medicine, said he hoped his research would change attitudes to obese people. (C)BBC

Keyword: Obesity; Development of the Brain
Link ID: 14469 - Posted: 09.20.2010

An IQ comparison shows that Canadian regulations on manganese in drinking water should be updated to protect children, Quebec researchers say. Manganese is a naturally occurring metal found in groundwater. It is an essential nutrient but, in excessive amounts, it can damage the nervous system. National and international guidelines for safe manganese levels in water should be revised, Quebec researchers say.National and international guidelines for safe manganese levels in water should be revised, Quebec researchers say. (CBC) Manganese occurs in naturally high levels in several parts of Quebec, New Brunswick and other regions, researchers say. Their study, published in Monday's online issue of the journal Environmental Health Perspectives, focused on manganese levels in drinking water in eight communities along the St. Lawrence River between Montreal and Quebec City. The water came from municipal wells and wasn't specially treated for manganese. "We found significant deficits in the intelligence quotient (IQ) of children exposed to higher concentration of manganese in drinking water," said the study's lead author, Maryse Bouchard of the University of Quebec at Montreal's Centre for Interdisciplinary Studies in Biology, Health, Society and Environment. © CBC 2010

Keyword: Development of the Brain; Neurotoxins
Link ID: 14468 - Posted: 09.20.2010

by Michael Le Page No one would believe that bacteria caused stomach ulcers – until Barry Marshall swallowed some BACK in 1984, a young Australian doctor called Barry Marshall swallowed a nasty-tasting solution of bacteria. This was no accident. He did it to convince his peers that his suspicions about a highly prevalent disease were not as far-fetched as they thought. In 1981, Marshall had met pathologist Robin Warren, who had found curved bacteria in inflamed stomach tissue. In further studies, they found that this bacterium, later named Helicobacter pylori, was present in most people who had inflammation or ulcers of the stomach or gut. Like two long-forgotten German researchers in 1875, they concluded that these bacteria were to blame. "I was met with constant criticism that my conclusions were premature," Marshall later wrote. "My results were disputed and disbelieved, not on the basis of science but because they simply could not be true." It is often claimed that doctors were wedded to the idea that ulcers were caused by excess stomach acid, or that they didn't believe that bacteria could grow in the stomach. In fact, the main reason for the scepticism, says Richard Harvey of the Frenchay Hospital in Bristol, UK, was that four-fifths of ulcers were not in the stomach but further down the digestive tract. © Copyright Reed Business Information Ltd.

Keyword: Stress
Link ID: 14467 - Posted: 09.20.2010

By Steve Connor The scourge of premenstrual tension, which affects more than half of women and causes physical as well as emotional trauma, could soon be eradicated by a safe, low-dose pill, scientists said yesterday. A laboratory-based study has found that very low doses of the anti-depression drug Prozac can eliminate the symptoms of premenstrual syndrome, which include mood swings, tiredness, irritability, headaches and joint pains. The scientist leading the research said the findings, which have so far been observed in laboratory rats, are strong enough to warrant a full-scale clinical trial with Prozac given that the drug has already undergone the necessary safety tests at the higher doses needed to treat depression. A clinical trial could begin within six months, and if the results are favourable, women could be taking the drug to treat premenstrual syndrome within two years, said Thelma Lovick, a neuroscientist at the University of Birmingham, who led the study. Not all women have the monthly symptoms associated with their menstrual cycle, but it is estimated that 75 per cent have experienced them at some time and that between 30 and 40 per cent have more severe symptoms that badly affect their work and family lives. The three-year study, funded by the Medical Research Council, has shown that Prozac taken in doses of about a tenth of that needed to treat depression can stop premenstrual symptoms in rats, animals which show physical and emotional changes, such as increased anxiety and sensitivity to pain, similar to those seen in women. Higher doses of Prozac have been prescribed to women suffering from premenstrual syndrome in the past, especially by doctors in the US, but usually for the treatment of more severe symptoms such as depression. ©independent.co.uk

Keyword: Depression; Hormones & Behavior
Link ID: 14466 - Posted: 09.18.2010

By Katherine Harmon When answering a question, your accuracy in assessing whether you have gotten the answer right—or wrong—might depend on the volume of gray matter in a certain part of your brain, according to a new study. Introspection—or metacognition, self-awareness about one's thinking—is a high-level mental process. "Accurate introspection requires discriminating correct decisions from incorrect ones, a capacity that varies substantially across individuals," researchers behind the new findings explained in their study. For the study, researchers used simple visual stimuli to test 32 healthy subjects' perception—and how confident they felt about their assessment of a geometric image. The tests were customized to each individual's level of perceptual skill, in order to keep each subject's accuracy score at 71 percent, so that the test was consistently difficult for all subjects. "Someone who has good introspective ability will accurately be able to know" if they were correct in their assessment of an image, explains Steven Fleming, a cognitive neuroscientist at the Wellcome Trust Centre for Neuroimaging at University College London and co-author of the new study. The study team found "considerable variation" in subjects' accuracy in assessing their own evaluations of the images, which was to be expected based on previous research. Fleming and his colleagues used magnetic resonance imaging (MRI) to evaluate the subjects' whole brains for differences in structure and composition in order to look for correlations with introspective ability. © 2010 Scientific American,

Keyword: Attention
Link ID: 14465 - Posted: 09.18.2010

by Roger Highfield Before winning his Nobel prize, Stanley Prusiner was ridiculed for suggesting that something he called a prion caused spongiform brain diseases WHEN the evidence suggested that the baffling "spongiform" brain disorders Creutzfeldt-Jakob disease (CJD), kuru and scrapie could not be transmitted by a virus or bacterium, the neurologist Stanley Prusiner put forward a novel type of infectious agent as the cause: a rogue protein. It was an idea considered so outrageous that Prusiner was ridiculed. Prusiner first began to study these diseases in 1972, after one of his patients at the University of California, San Francisco, died of CJD. A decade later, in the journal Science (vol 216, p 136), he suggested that these diseases were caused by a "proteinaceous infectious particle", or prion. The idea built on the findings of British researchers. In 1967, Tikvah Alper of the Medical Research Council's Radiopathology Unit showed that whatever it was that caused CJD was unscathed by levels of ultraviolet radiation that would destroy any genetic material (Nature, vol 214, p 764). Shortly afterwards, mathematician John Stanley Griffith of Bedford College in London devised a protein-only hypothesis for scrapie propagation. His 1967 Nature paper (vol 215, p 1043) states there was no reason to fear that the idea "would cause the whole theoretical structure of molecular biology to come tumbling down". © Copyright Reed Business Information Ltd.

Keyword: Prions
Link ID: 14464 - Posted: 09.18.2010

By Gwyneth Dickey Scientists have uncovered a new chemical process that may explain how antidepressants like Prozac work. The newly found mechanism also suggests why the drugs take weeks to start helping and may one day point to new therapies for depression. A team from Paris has found that fluoxetine, commonly known as Prozac, increases the amount of a particular microRNA called miR-16 in the brain. A microRNA is a small piece of RNA that prevents the translation of messenger RNA into protein. The miR-16 microRNA slows the formation of a cleaner-upper protein called the serotonin transporter. The protein clears away serotonin, a chemical that helps brain cells communicate and alleviates depression, from the space between brain cells. With less of the cleaner-upper to gobble up serotonin in the brain, there’s more serotonin in the spaces between brain cells, and depression symptoms lessen for some patients. The results are published in the Sept. 17 Science. “It’s an exciting development,” says pharmacologist Alan Frazer of the University of Texas Health Science Center at San Antonio. “As far as I know, it’s the first demonstration of a microRNA able to affect serotonin transporter expression.” Scientists knew that Prozac and other drugs like it, called selective serotonin reuptake inhibitors or SSRIs, somehow blocked the action of the serotonin transporter and left more serotonin in the brain. But exactly how the drugs worked, and why they took so long to have an effect, was a mystery. © Society for Science & the Public 2000 - 2010

Keyword: Depression
Link ID: 14463 - Posted: 09.18.2010

Men with low levels of stress are more attractive to women, according to research at the University of Abertay. The team analysed hormone levels in young men and showed pictures to a group of women. It found a strong link between low levels of the stress hormone cortisol in men and how attractive they were to the opposite sex. The research also discovered no link between high levels of the sex hormone testosterone and sex appeal. Dr Fhionna Moore, a psychology lecturer at Abertay University who lead the research team, said that previous studies had suggested a link between high levels of testosterone and greater health benefits as it was thought that only males with a strong immune system could cope with higher levels of the sex hormone. She said the university's study debunked that suggestion saying: "We analysed different levels and combinations of cortisol and testosterone and found a strong link between low cortisol levels, which is present when someone has low stress levels, and being highly attractive to women." The study also showed that female attraction to men with low stress levels was at its highest during the fertile phase of their cycle. (C)BBC

Keyword: Sexual Behavior; Stress
Link ID: 14462 - Posted: 09.16.2010

A small number of autism cases are linked to a gene found on the X chromosome, a discovery that may help explain why boys are four times more likely than girls to develop the disorder. There is no one gene responsible for autism spectrum disorder, or ASD. People with the disorder may have mild to severe symptoms that inhibit a person's ability to communicate and develop social relationships, which is often accompanied by behavioural challenges. In some people the disorder has a strong inherited component. Now, in Wednesday's online issue of the journal Science Translational Medicine, researchers at Toronto's Hospital for Sick Children, the Centre for Addiction and Mental Health and others report specific genetic alterations on the X chromosome that increase the risk of developing autism. Females carry two copies of the X chromosome, so they have a backup. Males, however, have only one X from their mothers and one Y from their fathers. So males who would inherit the genetic change from their mother are not protected, said the study's co-senior author, Prof. Stephen Scherer, senior scientist and director of the Centre for Applied Genomics at Sick Kids. About one in 70 baby boys will develop ASD, Scherer said in an interview. "So we've now identified the genetic cause in one per cent of those individuals, so in fact it's actually a large proportion of the population," Scherer said, meaning this newly identified mutation likely accounts for the biggest proportion of genes associated with autism. © CBC 2010

Keyword: Autism; Genes & Behavior
Link ID: 14461 - Posted: 09.16.2010

Characterized by paranoia, anxiety, hallucinations and delusions, schizophrenia and schizoaffective disorder, a related condition, are complicated mental illnesses that make it difficult for one to determine the difference between reality and pretend. While there are medications and therapies that can help, the effects of this condition are often far- reaching. Here, seven men and women speak about living with schizophrenia or schizoaffective disorder. Copyright 2010 The New York Times Company

Keyword: Schizophrenia
Link ID: 14460 - Posted: 09.16.2010

By Gary Stix What is a fate as bad as death? Many contemporary and ancient societies considered banishment at least equal. After all, in the past, estrangement from family or friends, along with the corresponding exile away from the campfire or town gates, meant literally getting thrown to the wolves. Not surprisingly, our brains are wired with circuitry so that we can scrupulously avoid such fates, whether that means expulsion to the desert as in the Biblical tale of Hagar and Ishmael or the heartbreak of not getting that long-awaited invitation to the high school prom. The neurological wiring that makes us feel pain, new research suggests, also means that a common painkiller could ease the sting. One brain area in question resides about an inch behind your forehead. Called the anterior cingulate cortex, it serves as one of the brain’s control centers for that “why me?” feeling when you get picked last for the dodgeball game. It also happens to be the same circuitry that induces the emotional component of pain, that desperate feeling provoked by the throbbing of a toothache. Evolution may have piggybacked brain functions that regulate social interaction on top of a more primal pain system. The way we speak (“I’m crushed”) even hints at just such a connection. Research from the 1970s in rodents on the overlapping functions of this brain circuitry showed that opiates tended to quell not only painful stimuli but also the tiny squeaks that signal distress. C. Nathan DeWall, a social psychologist at the University of Kentucky who has researched the neurobiology of rejection for nearly 10 years, wondered whether an extraordinarily simple step to tone down these double-duty pain circuits might work in the human brain, which has evolved to master playground politics and other complex behaviors. Instead of dosing subjects with Vicodin, he and colleagues simply handed out acetaminophen (Tylenol) or a placebo to 62 volunteers. “We didn’t have to use fancy drugs; we didn’t have to get prescriptions,” he says. © 2010 Scientific American, a division of Nature America,

Keyword: Pain & Touch; Emotions
Link ID: 14459 - Posted: 09.16.2010

By Jesse Bering There are signs, some would say omens, glimmering in certain children’s demeanors that, probably ever since there were children, have caused parents’ brows to crinkle with worry, precipitated forced conversations with nosy mothers-in-laws, strained marriages and ushered untold numbers into the deep covenant of sexual denial. We all know the stereotypes: an unusually light, delicate, effeminate air in a little boy’s step, often coupled with solitary bookishness, or a limp wrist, an interest in dolls, makeup, princesses, dresses and a staunch distaste for rough play with other boys; in little girls, there is the outwardly boyish stance, perhaps a penchant for tools, a lumbering gait, a square-jawed readiness for physical tussles with boys, an aversion to all the perfumed, delicate, laced trappings of femininity. So let’s get down to brass tacks. It’s what these behaviors signal to parents about their child’s incipient sexuality that makes them so undesirable—these behavioral patterns are feared, loathed and often spoken of directly as harbingers of adult homosexuality. However, it is only relatively recently that developmental scientists have conducted controlled studies with one clear aim in mind, which is to go beyond mere stereotypes and accurately identity the most reliable signs of later homosexuality. In looking carefully at the childhoods of now-gay adults, researchers are finding an intriguing set of early behavioral indicators that homosexuals seem to have in common. And, curiously enough, the age-old homophobic fears of parents seem to have some genuine predictive currency. © 2010 Scientific American, a division of Nature America,

Keyword: Sexual Behavior; Development of the Brain
Link ID: 14458 - Posted: 09.16.2010

By Tina Hesman Saey Chemical modifications to DNA may affect the activity of key genes involved in regulating body weight, a study finds, raising the possibility that scientists could discover environmental factors beyond calorie intake and exercise that influence a person’s size. The study, published September 15 in Science Translational Medicine, is also the first to demonstrate that these chemical modifications to DNA are unique to an individual and may affect a person’s risk of developing common diseases. Referred to as epigenetic, these changes don’t alter the DNA sequence itself but the way genes are turned on and off. Studying epigenetic marks may help scientists learn more about the causes of disease, says Michael Skinner, an epigenetics researcher at Washington State University in Pullman who was not part of the new study. “There’s a great deal of disease that is directly influenced by the environment that today we can’t explain just using genetics,” he says. In the study, researchers from Johns Hopkins University mapped one type of epigenetic change known as methylation in DNA samples taken 11 years apart from 74 Icelandic people. Methylation generally has the effect of turning off nearby genes. The team surveyed about 4.5 million spots on the genome of each person and determined how much of the DNA at each location carried marks of methylation. The amount of methylation varied among people at 227 of those spots, dubbed variably methylated regions or VMRs. Each person had a unique combination of these regions. © Society for Science & the Public 2000 - 2010

Keyword: Obesity; Genes & Behavior
Link ID: 14457 - Posted: 09.16.2010