Sandrine Ceurstemont, Dolphins keep amazing people with their clever tricks. Now it seems they can even copy the moves of others without needing to see them (see video above). A team at the Dolphin Research Center in Grassy Key, Florida, conducted the first experiment with blindfolded dolphins to investigate how they imitate others. Although they are known to mimic sounds and actions, it's unclear exactly what senses they use to do this. A dolphin called Tanner that had previously been trained to imitate other dolphins visually was chosen for the task. When his trainer gives a hand signal, Tanner knows to copy the moves of the dolphin next to him. To see how he performed without sight, his eyes were covered with plastic eye cups after he was given the cue. Then a second dolphin performed an action, or produced a sound Tanner was familiar with, and the researchers observed his ability to replicate it. Unsurprisingly, the team found that he had no problem reproducing sounds blindfolded. But he also reproduced a lot of actions with his eyes covered up, and even when he made mistakes the move wasn't too far off. "Since we know he wasn't using sight, he had to be using sound," says Kelly Jaakkola, a member of the team. "Either by recognising the characteristic sound that the behaviour makes, like you or I may recognise the sound of hands clapping, or by using echolocation." © Copyright Reed Business Information Ltd.

Keyword: Animal Communication; Language
Link ID: 14904 - Posted: 01.24.2011

by Linda Geddes Chemical messengers from the immune system can wreak emotional havoc if they cross into the brain – even in people who otherwise seem healthy When we get sick, we often feel lethargic and lose our appetites. Our concentration suffers and we might feel anxious, depressed or anti-social. These changes are caused by signalling molecules called cytokines, which are released by immune cells in response to stress and infection. Although cytokines are too large to pass freely through the blood-brain barrier, recent studies have shown that they can enter through naturally occurring leaky regions and via specialised channels. They can also affect nerves that transmit signals into the brain. There is growing evidence that cytokines associated with inflammation can cause depression. For instance, if you inject a healthy person with interferon-alpha, an antiviral drug that prompts the release of inflammatory cytokines, they will begin to show symptoms of depression (Brain Behavior and Immunity, vol 23, p 149). "Cytokines can interact with virtually every pathway relevant to depression," says Andrew Miller of Emory University School of Medicine in Atlanta, Georgia. And the idea that inflammation induces behavioural changes makes evolutionary sense too, he says. "Cytokines are trying to shut your body down so that you can devote your resources to healing. But at the same time, a wounded animal is a target so it needs to be hyper-alert in case a predator comes onto the scene." © Copyright Reed Business Information Ltd.

Keyword: Depression; Neuroimmunology
Link ID: 14903 - Posted: 01.24.2011

by Greg Miller There's a stark contrast in the media coverage of yesterday's FDA advisory committee meeting on a test for a signature feature of Alzheimer's disease. At The New York Times, Gina Kolata's cup of enthusiasm is at least half full: F.D.A. Sees Promise in Alzheimer's Imaging Drug An advisory committee to the Food and Drug Administration recommended unanimously Thursday that the agency approve the first test--a brain scan that can show the characteristic plaques of Alzheimer's disease in the brain of a living person. The approval was contingent on radiologists agreeing on what the scans say and doctors being trained in how to read the scans. The article quotes Alzheimer's experts enthusing about "a monumental step forward," and "a landmark day for our field." Several other outlets, including CNN Health, took more of a glass-half-empty approach: FDA on new Alzheimer's test: No, or at least not yet A new test to detect or rule out Alzheimer's is not quite ready for prime time, an FDA advisory panel said Thursday afternoon. The test, a type of PET scan developed by Avid Radiopharmaceuticals, is designed to detect the telltale buildups of amyloid plaque in the brain that signify Alzheimer's disease. © 2010 American Association for the Advancement of Science.

Keyword: Alzheimers
Link ID: 14902 - Posted: 01.24.2011

By SUZETTE LABOY GRASSY KEY, Fla. -- In a lagoon in the Florida Keys, trainer Emily Guarino blindfolds a male dolphin named Tanner with special latex goggles. "You ready, Tanner?" Guarino asks the young dolphin, waiting beside his companion Kibby. At a command, another trainer gets Kibby to say 'hello' by flapping his fins on the water, splashing noisily in the enclosed lagoon at the Dolphin Research Center here, which houses 22 dolphins and is one of the leaders in dolphin cognitive studies. "Can you imitate what Kibby is doing?" Guarino asks Tanner. Within seconds, Tanner is splashing "hello" - a seemingly extraordinary feat given the blindfolded dolphin appears to only be using sound to perceive and imitate the actions of his fellow dolphin. It turns out dolphins are master imitators that somehow can "see" their environment despite blindfolds. But exactly how such a dolphin can mimic another's action is a matter of ongoing scientific study. Dr. Kelly Jaakkola, director of the nonprofit marine mammal research center, said the research to better understand dolphin intelligence will surely help further their conservation. She said such study may also be helpful in better grasping the complexities of human intelligence. "It's human nature to care more about animals we perceive as intelligent. So the more we can showcase that intelligence we give people a way to connect, to care and therefore conserve," she said. Copyright 2011 Miami Herald Media Co.

Keyword: Hearing; Vision
Link ID: 14901 - Posted: 01.24.2011

By Neil Bowdler Science reporter, BBC News Researchers in the United States say they have uncovered tentative evidence of a genetic component to friendship. Using data from two independent studies, they found carriers of one gene associated with alcoholism tended to stick together. However, people with another gene linked with metabolism and openness, stayed apart. Details are published in the journal Proceedings of the National Academy of Sciences. The researchers looked at six genetic markers in two long-running US studies, the National Longitudinal Study of Adolescent Health and the Framingham Heart Study, which contain both genetic data and information on friends. With one gene, called DRD2, which has been associated with alcoholism, they found clusters of friends with the very same marker. Another gene called CYP2A6, which has a suspected role in the metabolism of foreign bodies including nicotine, appeared more divisive. People with this gene seemed to steer clear of those who also carry the gene. Why, the researchers don't know, but they speculate it could form part of a defensive ploy. They say similar patterns have been observed among couples, with individuals avoiding prospective partners who are susceptible to the same diseases. BBC © MMXI

Keyword: Genes & Behavior
Link ID: 14900 - Posted: 01.21.2011

Alan Boyle If you have a knack for knowing just the right move to make — in a board game or in other walks of life — it might be because your brain has built up a special kind of connection. Researchers at Japan's RIKEN Brain Science Institute report evidence that the professional players of a chesslike board game from Japan, known as shogi, have brains that crackle with activity in two areas that are less active in amateurs. Their findings are published in this week's issue of the journal Science. The activity was monitored using functional magnetic resonance imaging, or fMRI, while professionals and amateurs were shown pictures of shogi board patterns. Shogi is regarded as a game as cerebral and as tricky to master as chess — perhaps even more tricky, because players can add pieces captured from an opponent to their own side. The professionals were more adept at intuitively recognizing the "next best move" for a given pattern, but the really interesting part of this game had to do with what went on in their brains. The pros' brains showed more activity in the precuneus region of the parietal lobe, which has been linked to pattern recognition, as well as in the head of the caudate nucleus, deep within the brain. The caudate nucleus has been previously linked with cognitive functions, and game-playing in particular In fact, a different team of researchers reported last year that people who showed an aptitude for arcade games tended to have a bigger caudate nucleus (along with other structures) than less skilled players. © 2011 msnbc.com

Keyword: Attention; Brain imaging
Link ID: 14899 - Posted: 01.21.2011

By GINA KOLATA An advisory committee to the Food and Drug Administration recommended unanimously Thursday that the agency approve the first test — a brain scan — that can show the characteristic plaques of Alzheimer’s disease in the brain of a living person. The approval was contingent on radiologists agreeing on what the scans say and doctors being trained in how to read the scans. The F.D.A. usually follows advice from its advisory committees, and Alzheimer’s experts anticipated that the scans would be approved. The additional requirement would not be a big hurdle, said Dr. Daniel M. Skovronsky, chief executive of the company, Avid Radiopharmaceuticals, that applied to market the scans. “We don’t know exactly what F.D.A. will want,” Dr. Skovronsky said. “But it should take months to generate this type of data, not years.” The committee vote is “a very positive thing,” said Maria Carrillo, senior director of medical and scientific relations for the Alzheimer’s Association. “This is nothing but a positive for our families.” More than five million Americans have Alzheimer’s disease. Plaques are part of the criteria for having Alzheimer’s — if a person with memory problems does not have plaques, that person does not have Alzheimer’s. But without the scan, the only way to know if plaques were present is to do an autopsy. Alzheimer’s specialists said they expected that if the scan were approved it would come into widespread use. © 2011 The New York Times Company

Keyword: Alzheimers; Brain imaging
Link ID: 14898 - Posted: 01.21.2011

The effectiveness of an experimental treatment for alcoholism depends on the genetic makeup of individuals who receive it, according to a new study supported by the National Institute on Alcohol Abuse and Alcoholism (NIAAA), part of the National Institutes of Health. A report of the findings appears online in the American Journal of Psychiatry. Researchers led by Bankole Johnson, M.D., Ph.D., professor and chair of the Department of Psychiatry and Neurobehavioral Sciences at the University of Virginia, Charlottesville, conducted a controlled trial to determine if the medication ondansetron could reduce problem drinking, in alcohol-dependent individuals. Ondansetron is currently used to treat nausea and vomiting, often following chemotherapy. It works by blocking receptors for the brain chemical serotonin. The current study extends the researchers’ previous work on the role the brain’s serotonin system plays in alcohol misuse. Serotonin mediates many processes in the brain, including the rewarding effects of alcohol. Dr. Johnson’s group has shown that variations in the gene that encodes the serotonin transporter, a protein that regulates the concentration of serotonin between nerve cells, can significantly influence drinking intensity. Specifically, serotonin transporter variants designated as LL and TT have been associated with more severe drinking problems. The researchers have also reported that ondansetron may be an effective therapy for some people with alcoholism. In this study, Dr. Johnson and his colleagues performed genetic analyses to determine which serotonin transporter gene variants were carried by each subject, then randomly assigned each subject to treatment regimens with ondansetron or placebo.

Keyword: Drug Abuse; Genes & Behavior
Link ID: 14897 - Posted: 01.21.2011

By Laura Spinney Scientists have long known that people perceive scents differently. But emerging evidence from several large-scale studies shows that the variation is larger than previously known. It turns out that people differ in how they perceive many if not all odors, and most of us have at least one scent we cannot detect at all. “Everybody’s olfactory world is a unique, private world,” says Andreas Keller, a geneticist at the Rockefeller University. Over the course of evolution, partly because humans grew more reliant on vision and smell became relatively less important, the genes encoding our 400 or so olfactory receptors began to accumulate mutations. Once a gene has accumulated enough mutations, it becomes a “pseudogene,” notes geneticist Doron Lancet of Israel’s Weizmann Institute of Science, meaning it no longer encodes a functioning receptor. Different people have different combinations of pseudogenes, however. “You end up with a bar code situation, whereby each individual has a slightly different bar code,” he says. That genetic variability seems to translate into behavioral variability. When Keller and his colleagues asked 500 people to rate a panel of 66 odors for intensity and pleasantness, they gave the full range of responses—from weak to intense and from pleasant to unpleasant. In an ongoing study at the University of Dresden, Thomas Hummel and his associates have tested 1,500 young adults on a panel of 20 odors and found specific insensitivities to all but one—citralva, which has a citrus smell. Based on these findings, Keller suspects that each person has an olfactory blind spot. © 2011 Scientific American, a Division of Nature America, Inc.

Keyword: Chemical Senses (Smell & Taste); Genes & Behavior
Link ID: 14896 - Posted: 01.21.2011

(Relaxnews) - If you're trying to quit smoking, it's probably best to switch off the TV and avoid watching films, a new study suggests. Previous research has reported that watching actors puff cigarettes on screen (Mad Men anyone?) triggers cravings in smokers, but a new study published January 19 points to why. According to the research, watching actors smoke cigarettes activates the part of the brain that plans hand movements in smokers, such as movements required for lighting up and taking a drag. US researchers selected the 2003 Nicolas Cage film Matchstick Men because smoking plays a prominent role in the film, but sex, violence, and alcohol abuse don't, which researchers feared would skew the results. The study was published in the Journal of Neuroscience. To find out what happens in the brain when watching onscreen smoking, the researchers asked 17 smokers and 17 nonsmokers to watch the first 30 minutes of the movie while in a functional magnetic resonance imaging machine (fMRI), which measures blood flow to different areas of the brain as a way to track brain activity. The scans revealed that smokers' brains went into action, already planning the movements of their smoking hand, which was not the case for the nonsmokers. The volunteers did not know the experiment was about smoking. The Guardian reports that cigarette smoking is a habit that kills five million people worldwide each year. In 2010, the US Centers for Disease Control and Prevention claimed that smoking scenes encouraged children and adolescents to light up. While smoking on television and in movies may have become less common in recent years, the organization states that around half of the popular US movies in 2009 involved smoking scenes. © 2011 NY Times Co.

Keyword: Drug Abuse
Link ID: 14895 - Posted: 01.21.2011

By Rachel Ehrenberg A nip of Pernod or Ouzo before dinner to stimulate the appetite may be a sound strategy. When mouse gut cells are stimulated with bitter compounds they trigger secretion of a hunger hormone, researchers report online January 18 in the Proceedings of the National Academy of Sciences. Whetting the appetite with a before-dinner drink, or aperitif — from the Latin aprire, to open — has long been associated with improved digestion. The often bitter drinks typically contain a secret mixture of herbs and spices, sometimes to deliberately quell the taste of another common aperitif ingredient — quinine. Quinine is one of a number of compounds that stimulate the bitter taste receptors — cells that, in the mouth, are seen as a first line of defense against ingesting toxins. So scientists thought that eating such compounds would inhibit appetite, not rev it up. But when mice were fed a bitter mixture, their levels of the hunger hormone ghrelin spiked, a research team from the Catholic University of Leuven in Belgium reports. These mice then went on a half-hour eating binge, unlike counterparts that had impaired machinery for sensing bitter compounds. Oddly, this binge was followed by several hours of fasting, and experiments revealed a delay in digestion of the large meal. © Society for Science & the Public 2000 - 2011

Keyword: Chemical Senses (Smell & Taste); Obesity
Link ID: 14894 - Posted: 01.21.2011

By Nathan Seppa Antibodies generated by a new vaccine can capture molecules of cocaine in the precious few seconds that lapse before the drug reaches the brain, a study in mice shows. Although the antibody brigade doesn’t snag all the cocaine, it seems to collar enough to greatly subdue the agitation that mice exhibit when given the drug. Based on these findings, the researchers are moving on to studies in rats and monkeys in hopes of testing the vaccine in people. The new report will appear in the March Molecular Therapy. “When someone takes cocaine — whether snorted, smoked or injected — you don’t have much time,” says study coauthor Ronald Crystal, a pulmonary physician at Weill Cornell Medical College in New York City. “It takes about six second to pass from the lungs to the blood to the brain.” A vaccine would need to elicit a standing army poised to intercede. “You need avid antibodies, at high levels,” Crystal says. In the new study, Crystal and his colleagues gave mice three injections over six weeks. Some of the animals received a placebo while the others got the experimental vaccine, which combines a cocainelike substance with portions of an adenovirus that stimulate an immune response but don’t cause disease. Seven weeks later, all the mice were exposed to cocaine by injection. © Society for Science & the Public 2000 - 2011

Keyword: Drug Abuse
Link ID: 14893 - Posted: 01.21.2011

By Tina Hesman Saey Staying up all night clearly taxes the body, but scientists have only now added up the exact bill. By measuring the actual number of calories the body expends to fuel an all-nighter versus a good night’s sleep, researchers from the University of Colorado at Boulder calculate that a full night of sleep helps the body conserve as much energy as is in a glass of warm milk. Missing a night of sleep forces the body to burn about an extra 161 calories than it would have during eight hours of sleep (not counting what’s used in moving around while awake), but it’s no weight-loss miracle: The body tries to make up for the deficit by saving more energy than usual the next day and night, researchers report in the January Journal of Physiology. The measurements, the first to put precise numbers on how much total energy people use in a 24-hour period while asleep, awake or recovering from a night of sleep deprivation, help bolster a theory that an important function of sleep is to save energy (SN: 10/24/09, p. 16). To measure how much energy people use during sleep in a more rigorous way than has been done before, Kenneth Wright, a physiologist at the University of Colorado, and his colleagues studied seven people. Each of the healthy young volunteers lived inside a sealed room for three days. The volunteers were on bed rest the entire time and ate the same amount of calories at the same time each day. The researchers continually monitored the subject’s brain waves and how much oxygen and carbon dioxide the person breathed in and out. From there, the team could calculate each person’s energy use during each stage of sleep and waking. © Society for Science & the Public 2000 - 2011

Keyword: Obesity; Sleep
Link ID: 14892 - Posted: 01.21.2011

by Wendy Zukerman After only 12 generations of practising polygamy male mice are much more fertile than their monogamous brethren. That is the conclusion of the first study to provide concrete evidence for the evolutionary theory which proposes that competition for mates will increase male fertility, says Leigh Simmons at the University of Western Australia, Australia. House mice (Mus domesticus) can swap between being polygamous and monogamous. To see if this had an impact on their sperm quality, Simmons and his colleague Renee Firman created polygamous and monogamous breeds and compared their fertility. For the "monogamous" mice, they paired 18 males with 18 female mice, then took two offspring from each monogamous couple – one male and one female – and bred them with the offspring of another monogamous couple. The experiment was repeated for 12 generations. For "polygamous" mice, each female was sequentially mated with three males, and this, too, was repeated for 12 generations. At the end of breeding, all mice were the same size and weight. Sperm success Next came the ultimate test: would sperm from polygamous males be more successful at producing offspring than sperm from monogamous mice? © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior; Evolution
Link ID: 14891 - Posted: 01.21.2011

by Rachel Courtland "BIRD brain" is usually an insult, but that may have to change. A light-activated compass at the back of some birds' eyes may preserve electrons in delicate quantum states for longer than the best artificial systems. Migrating birds navigate by sensing Earth's magnetic field, but the exact mechanisms at work are unclear. Pigeons are thought to rely on bits of magnetite in their beaks. Others, like the European robin (pictured), may rely on light-triggered chemical changes that depend on the bird's orientation relative to Earth's magnetic field. A process called the radical pair (RP) mechanism is believed to be behind the latter method. In this mechanism, light excites two electrons on one molecule and shunts one of them onto a second molecule. Although the two electrons are separated, their spins are linked through quantum entanglement. The electrons eventually relax, destroying this quantum state. Before this happens, however, Earth's magnetic field can alter the relative alignment of the electrons' spins, which in turn alters the chemical properties of the molecules involved. A bird could then use the concentrations of chemicals at different points on its eye to deduce its orientation. Intrigued by the idea that, if the RP mechanism is correct, a delicate quantum state can survive a busy place like the back of an eye, Erik Gauger of the University of Oxford and colleagues set out to find out how long the electrons remain entangled. © Copyright Reed Business Information Ltd.

Keyword: Animal Migration; Vision
Link ID: 14890 - Posted: 01.21.2011

by Carl Zimmer Imagine that an eccentric psychologist accosts you. In his hand is a piece of paper with 20 pictures of roses. One of the pictures shows a rose in the flower bed you just passed, he says, and he asks you to pick its picture out from his lineup. The challenge would seem absurd—but if you were to change the roses to faces, nearly everyone could meet it. Most of us have a powerful ability to recognize faces, and yet we hardly ever take note of it. We can commit a face to memory with a single viewing, and even if we see that face only once its memory can stay fresh for years. The faces we remember so easily may differ only in subtle tweaks of geometry: the ratio of distances between different landmarks such as the eyes and the mouth, for example. A small fraction of people, however, cannot recognize faces—even the faces of their parents, spouses, and children. Prosopagnosia, as this condition is known, can affect people from birth or be triggered later in life by injuries to the brain. It strikes an estimated 2 percent of Americans and is often accompanied by other types of recognition impairments, including difficulty recognizing places and objects, such as cars. Despite the millions of people who suffer from prosopagnosia, it remains an obscure disorder, probably due to the skill with which face-blind people quietly compensate for their condition. In his new book, The Mind’s Eye (Amazon; book review in The New York Times), neurologist and writer Oliver Sacks makes the surprising disclosure that he has prosopagnosia. © 2011, Kalmbach Publishing Co.

Keyword: Attention; Laterality
Link ID: 14889 - Posted: 01.21.2011

By Kevin Mitchell What if your brain knew something but couldn’t tell you? New research suggests that this is exactly what may be behind two rather curious conditions. Most of us are familiar with people who are tune deaf – these are the people who not only cannot sing in tune but are also unaware of that fact. Individuals with severe forms of this condition, known as amusia, are unable to detect whether particular notes within a melody are out of tune or out of key. Many are also unable to recognise melodies without lyrics or to hold a tune in their heads, even if they have just heard it. These difficulties arise despite normal hearing and also a fairly normal ability to hear the difference between isolated tones. The defect lies in connecting this sensory input with some implicit knowledge of musical structure and contours. Amusia thus falls into a class of conditions known as agnosias, which are characterised by the lack of knowledge of some, often very specific, category of object. Another, equally curious, example of this class of condition is prosopagnosia – the lack of knowledge of faces. People with severe prosopagnosia may be completely unable to recognise the faces of famous people, friends, loved ones, even their own faces. As with amusia, this reflects a high-level deficit – people with prosopagnosia have normal vision and the ability to distinguish specific facial features, gender, even facial emotions. Both conditions thus seem to reflect the inability to link incoming sensory information (a person’s face or a specific note) with stored, implicit knowledge about that category (the person’s identity or a specific melody or general rules of melodic stucture). © 2011 Scientific American, a Division of Nature America, Inc.

Keyword: Hearing; Attention
Link ID: 14888 - Posted: 01.21.2011

By NICHOLAS WADE Chaser, a border collie who lives in Spartanburg, S.C., has the largest vocabulary of any known dog. She knows 1,022 nouns, a record that displays unexpected depths of the canine mind and may help explain how children acquire language. Chaser belongs to John W. Pilley, a psychologist who taught for 30 years at Wofford College, a liberal arts institution in Spartanburg. In 2004, after he had retired, he read a report in Science about Rico, a border collie whose German owners had taught him to recognize 200 items, mostly toys and balls. Dr. Pilley decided to repeat the experiment using a technique he had developed for teaching dogs, and he describes his findings in the current issue of the journal Behavioural Processes. He bought Chaser as a puppy in 2004 from a local breeder and started to train her for four to five hours a day. He would show her an object, say its name up to 40 times, then hide it and ask her to find it, while repeating the name all the time. She was taught one or two new names a day, with monthly revisions and reinforcement for any names she had forgotten. Border collies are working dogs. They have a reputation for smartness, and they are highly motivated. They are bred to herd sheep indefatigably all day long. Absent that task, they must be given something else to do or they go stir crazy. Chaser proved to be a diligent student. Unlike human children, she seems to love her drills and tests and is always asking for more. “She still demands four to five hours a day,” Dr. Pilley said. “I’m 82, and I have to go to bed to get away from her.” © 2011 The New York Times Company

Keyword: Language; Evolution
Link ID: 14887 - Posted: 01.18.2011

Obesity is one the last forms of discrimination that society readily accepts, and that's no laughing matter, a Canadian summit heard Monday. The Canadian Obesity Network, an advocacy group that organized the conference in Toronto, is considering calling for federal legislation that would make it illegal for employers to discriminate against overweight Canadians, a move the state of Michigan has made. The network brought together some of North America's top obesity experts and people who struggle with weight issues in what the network says is the first Canadian conference to deal with weight bias and discrimination. Summit participant David Dolomont said he weighs more than 300 pounds and has faced taunts and jokes about his excess weight since childhood. "My mother would have to take me to that special store downtown to buy pants because I had to get into the so called 'husky size,' Dolomont recalled when he spoke about his experience at the conference. The discrimination didn't end with adulthood when he started to work as a paramedic in Hamilton, he said. Dolomont remembers feeling ashamed and embarrassed during a breakfast at work where he was singled out by a supervisor. "He saw me and then come over right away and said, 'Hey David glad you're here. We knew you were coming this morning so we asked them to put on a second cook and get some extra food in just because we knew you were going to be here today." © CBC 2011

Keyword: Obesity
Link ID: 14886 - Posted: 01.18.2011

A person's friends tend to share certain genes in common with each other — but not always with the individual, a new study suggests. "People’s friends may not only have similar traits, but actually resemble each other on a genotypic level," said the study led by James Fowler, a geneticist at the University of California at San Diego. The findings were published Friday in the Proceedings of the National Academy of Sciences. Researchers noticed two distinct patterns within social networks when it came to the genes DRD2, which has been linked to alcoholism, and CYP2AP, which is linked with the character trait of openness. In the case of DRD2, people with the marker tend to make friends with those who also have that marker. People without it tend to make friends with other DRD2-negative individuals. In the case of CYP2A6, the person who has the gene tends to be the hub of a social network made up of people who don't have it and instead share the opposite genotype. Four other genes examined by the researchers did not show such patterns among groups of friends. The analysis found that this gene clustering within social networks was apparent even when the researchers took into account the fact that people are more likely to make friends with people who live near them. The findings suggest that studies linking certain traits to genes may be biased in ways that were not previously anticipated. © CBC 2011

Keyword: Genes & Behavior
Link ID: 14885 - Posted: 01.18.2011