By Janet Raloff Being fat may diminish mental performance, studies find — a problem that worsens with age. But among elderly women, where fat is deposited may matter. To wit: The big apple is sharper than the obese pear. Genetics dictates where people preferentially accumulate body fat. For most it’s around the belly. Among the obese, these apple-shaped individuals tend to run a bigger risk of developing heart disease than do pears — people who deposit most of their excess fat at the hips and thighs. For a host of reasons, physicians had expected that if body shape affected mental performance, apples would again prove the bigger losers. In fact, the opposite appears true, Diana Kerwin of Northwestern University’s Feinberg School of Medicine in Chicago and her colleagues report online July 14 in the Journal of the American Geriatrics Society. The team pored over data collected from more than 8,700 women, all 65 to 79 years old. These were a healthy subset of incoming participants to the Women’s Health Initiative study. This long-running trial at 40 medical centers across the country has been investigating the role of hormone-replacement therapy and diet on risk of heart disease, fractures and certain cancers. Each woman was administered a test of memory and reasoning known as the Modified Mini-Mental State Examination, or 3MSE. Kerwin’s team correlated a participant’s score with her shape and her height-adjusted weight — something known as body-mass index, or BMI. BMI values were divided into six categories, with 1 being lean and 6 morbidly obese. © Society for Science & the Public 2000 - 2010

Keyword: Obesity; Learning & Memory
Link ID: 14261 - Posted: 07.15.2010

Having low vitamin D levels may increase a person's risk of developing Parkinson's disease later in life, say Finnish researchers. Their study of 3,000 people, published in Archives of Neurology, found people with the lowest levels of the sunshine vitamin had a three-fold higher risk. Vitamin D could be helping to protect the nerve cells gradually lost by people with the disease, experts say. The charity Parkinson's UK said further research was required. Parkinson's disease affects several parts of the brain, leading to symptoms like tremor and slow movements. The researchers from Finland's National Institute for Health and Welfare measured vitamin D levels from the study group between 1978 and 1980, using blood samples. They then followed these people over 30 years to see whether they developed Parkinson's disease. They found that people with the lowest levels of vitamin D were three times more likely to develop Parkinson's, compared with the group with the highest levels of vitamin D. Most vitamin D is made by the body when the skin is exposed to sunlight, although some comes from foods like oily fish, milk or cereals. As people age, however, their skin becomes less able to produce vitamin D. Doctors have known for many years that vitamin D helps calcium uptake and bone formation. But research is now showing that it also plays a role in regulating the immune system, as well as in the development of the nervous system. (C)BBC

Keyword: Parkinsons
Link ID: 14260 - Posted: 07.13.2010

by MARILYNN MARCHIONE MILWAUKEE, Wisconsin — Scientists are reporting advances in detecting and predicting Alzheimer's disease at a conference in Honolulu this week, plus offering more proof that getting enough exercise and vitamin D may lower your risk. There are better brain scans to spot Alzheimer's disease. More genes that affect risk. Blood and spinal fluid tests that may help tell who will develop the mind-robbing illness and when. But what is needed most — a treatment that does more than just ease symptoms — is not at hand. "We don't have anything that slows or stops the course," said William Thies, the Alzheimer's Association scientific director. "We're really in a silent window right now" with new drugs, he said. Several promising ones flopped in late-stage tests — most recently, Pfizer Inc.'s Dimebon. Results on several others won't be ready until next year. Still, there is some progress against Alzheimer's, a dementia that afflicts more than 26 million people worldwide. Highlights of the research being reported this week: Prevention. Moderate to heavy exercisers had half the risk of developing dementia compared with less active people, researchers from the long-running Framingham Heart Study reported Sunday. Earlier studies also found exercise helps. Copyright 2010 The Associated Press.

Keyword: Alzheimers
Link ID: 14259 - Posted: 07.13.2010

Steve Connor Huntington’s disease is a relatively rare genetic disorder that you wouldn’t wish upon your worst enemy. If you carry a single copy of the affected gene you are destined to die a horrible death involving uncontrollable movements, psychiatric disturbances and progressive dementia. The first symptoms typically occur around the age of 40, and it takes between 10 and 15 more years for the gradual neurodegeneration to end life. Ten years after the excitement of mapping the human genome, and the revolution in the understanding of genetic disorders that the achievement has brought, it is easy to forget that some of those directly affected by inherited diseases have seen little in terms of practical benefit. The gene involved in Huntington’s disease was mapped to chromosome 4 in 1983 by a team led by Jim Gusella at Harvard Medical School in Boston, but it took another 10 years of intensive effort to isolate and clone the gene itself. This allowed scientists to find the type of changes, or mutations, that cause the disorder – the mutated gene has about two or three times the normal number of ‘GAG repeats. I remember on both occasions – in 1983 and 1993 – there were optimistic predictions that the discoveries would soon lead to a test for the carriers of the Huntington’s mutation and effective treatments – even possibly a cure – for the disease. The sad fact is that although a relatively cheap and accurate diagnostic test for the Huntington’s mutation has existed for some years, this medical advance has for the affected families arguably produced more misery than it has eradicated. For a start, there has been no accompanying revolution in treatment, largely because there are so few affected people (estimated to be about 12,000 in Britain) to make it worth the expense and effort of the drug companies to develop new therapies. ©independent.co.uk

Keyword: Huntingtons; Genes & Behavior
Link ID: 14258 - Posted: 07.13.2010

By GINA KOLATA A small company with a new brain scan for detecting plaque, the hallmark physical sign of Alzheimer’s disease, presented its results on Sunday at an international conference in Hawaii, and experts who attended said the data persuaded them that the method works. Until now, the only definitive way to diagnose Alzheimer’s has been to search for plaque with a brain autopsy after the patient dies. Scientists hope the new scanning technique, described June 24 in The New York Times’s series “The Vanishing Mind,” will allow doctors to see plaque while the patient is still alive, improving diagnosis and aiding research on drugs to slow or stop plaque accumulation. Neurologists have known about plaques ever since Alzheimer’s disease was first described in 1906. They are microscopic bumps made up of a protein, amyloid beta, appearing on the surface of the brain in areas involved with learning and memory. They are so characteristic of Alzheimer’s that they are required for a definitive diagnosis of the disease. Of course, doctors do not wait for a brain autopsy to diagnose Alzheimer’s. They use memory tests and evaluations of patients’ reasoning and ability to care for themselves. Yet with autopsy, even doctors at leading medical centers have been wrong as often as 20 percent of the time: people they said had Alzheimer’s did not have plaque. Copyright 2010 The New York Times Company

Keyword: Alzheimers; Brain imaging
Link ID: 14257 - Posted: 07.13.2010

By Melody Dye Subject 046M, for male, was seated nervously across from me at the table, his hands clasped tightly together in his lap. He appeared to have caught an incurable case of the squirms. I resisted the urge to laugh, and leaned forward, whispering conspiratorially. “Today, we’re going to play a game with Mr. Moo” —I produced an inviting plush cow from behind my back. “Can you say hi to Mr. Moo?” In the Stanford lab I work in with Professor Michael Ramscar, we study how children go about what is arguably the most vital project in their career as aspiring adults—learning language. Over the last several years, we’ve been particularly taken with the question of how kids learn a small, but telling piece of that vast complex: color words. We want to know how much they know, when they know it, and whether we can help them get there faster. 046M was off to a good start. I arranged three different color swatches in front of him. “Can you show me the red one?” He paused slightly, then pointed to the middle rectangle: red . “Very good!” I said, beaming. “Now, what about the one that’s blue?” The test was not designed to trip kids up. Far from it—we only tested basic color words, and we never made kids pick between confusable shades, like red and pink. To an adult, the test would be laughably easy. Yet, after several months of testing two-year olds, I could count my high scorers on one hand. Most would fail the test outright. 046M, despite his promising start, proved no exception. © 2010 Scientific American,

Keyword: Development of the Brain; Vision
Link ID: 14256 - Posted: 07.13.2010

When a person loses his sense of smell, does he also lose any memory associated with a smell? —Ana Artega, via e-mail David Smith, a professor of psychology and a researcher at the Center for Smell and Taste at the University of Florida, replies: Normally people can detect a cacophony of odors using the 40 million olfactory receptor neurons that reside in the nasal cavity. When we encounter a new odor, these neurons send information about the whiff to a brain area called the olfactory cortex, leaving an imprint of the smell there. These memories accumulate over time to create a library of odors. Although we do not fully understand how the olfactory cortex encodes these memories, we do know that olfactory memories seem to be particularly rich—perhaps because the olfactory cortex is closely connected to the brain regions im­­portant for recollection. These areas include the amygdala, which processes emotions, and the hippocampus, which encodes and stores memories. Damage to the olfactory receptor neurons because of a respiratory infection, a head injury or a neurodegenerative disease can disrupt the brain’s ability to process different smells. When olfactory neurons stop working altogether, a person develops anosmia, or the inability to discern odors. According to a 2008 report from the National Institutes of Health, 1 to 2 percent of the U.S. population younger than 65 years old, and more than half older than 65, have almost completely lost their sense of smell. © 2010 Scientific American,

Keyword: Chemical Senses (Smell & Taste); Learning & Memory
Link ID: 14255 - Posted: 07.13.2010

By CLAUDIA DREIFUS Jeremy Niven spends his days at Cambridge University running locusts across ladders and through mazes, trying to figure out how bugs think. Dr. Niven, 34, studies the evolution of brains and neurons in insects and other animals, like humans. We spoke during a break in last month's World Science Festival in New York, where he was a guest presenter, and then again later via telephone. An edited version of the two conversations follows: Q. YOUR RESEARCH SUBJECTS ARE LOCUSTS. SOME PEOPLE MIGHT SAY, “LOCUSTS, YUCK!” WHY STUDY THEM? A. I think locusts are sweet. When you get used to them, they are actually quite nice. Actually, I find that working with invertebrates opens your mind. Insects don’t perceive the world the way we do. Trying to understand them makes you think more about why we see the world as we do. Many animals have different sensors and receive different energies. Birds have ultraviolet vision. So do bees. They can see things we don’t. One learns respect for their capacities. But the other thing is that insects in general and locusts in particular are admirable because they permit us to gain new information about nervous systems. With insects, we can actually study neural circuits and see how what happens in the neurons relates to behavior. Copyright 2010 The New York Times Company

Keyword: Learning & Memory; Evolution
Link ID: 14254 - Posted: 07.13.2010

By SINDYA N. BHANOO Handsome men may turn the heads of women, but for those less attractive, sociability and friendliness also seem to seduce the fairer sex. The same is true for male house finches, according to a new study. Female house finches prefer to mate with males with the reddest feathers, but dull-colored males make themselves more appealing by acting more social before mating season, according to a study in the September issue of the American Naturalist. The researchers found that the duller a male bird was in color, the more likely he was to engage with multiple social groups. Birds in a social group flock and forage together and any bird can belong to multiple groups. Drab-looking male finches drifted from group to group in the winter, the researchers found. By mating season in the spring, the less attractive males tended to have the same level of mating success as the most colorful, attractive males. “Females have limited options to chose from and this is a way for males to manipulate their chances to find mates, by placing themselves in certain settings,” said Kevin Oh, an evolutionary biologist at Cornell University and the study’s lead author. The least attractive, or most yellow, males were four times as likely to interact with multiple social groups then the most attractive, or reddest, males, Dr. Oh said. House finches are found across North America, but Dr. Oh and his co-author, Alexander Badyaev of the University of Arizona, studied wild populations in Arizona. Copyright 2010 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 14253 - Posted: 07.13.2010

by Linda Geddes A form of synaesthesia in which people experience letters or numbers in colour may be trainable. The discovery could shed new light on how such traits develop. Synaesthesia is thought to have a genetic component, but some people have reported synaesthetic experiences following hypnosis, so Olympia Colizoli at the University of Amsterdam in the Netherlands, and colleagues, wondered if it might also be possible to acquire synaesthesia through training. To test the idea, they gave seven volunteers a novel to read in which certain letters were always written in red, green, blue or orange (see picture). Before and after reading the book, the volunteers took a "synaesthetic crowding" test, in which they identified the middle letter of a grid of black letters which were quickly flashed onto a screen. Synaesthetes perform better on the test when a letter they experience in colour is the target letter. The volunteers performed significantly better on this test after training compared with people who read the novel in black and white. The findings suggest that natural synaesthesia may develop as a result of childhood experiences as well as genetics, says Colizoli, who presented the findings at the Forum of European Neuroscience in Amsterdam last week. © Copyright Reed Business Information Ltd.

Keyword: Miscellaneous
Link ID: 14252 - Posted: 07.13.2010

By Tina Hesman Saey Aging and wisdom are supposed to go together, but it turns out that a molecule that prevents one may actually play a role in the other. Researchers have discovered a new role for the famous antiaging protein SIRT1. It not only fends off aging, but also aids in learning and memory, a new study published online July 11 in Nature shows. Sirtuins, a family of proteins that includes SIRT1, help to regulate gene activity and have been implicated in governing metabolism and many of the biological processes that lead to aging. In the new study, Li-Huei Tsai, a neuroscientist and Howard Hughes Medical Institute investigator at MIT, finds that SIRT1 also plays a critical role in protecting learning and memory, at least in mice. Tsai and her colleagues had an inkling that SIRT1 might play some role in the brain from earlier experiments showing that resveratrol, an activator of sirtuins, could help neurons survive a mouse version of Alzheimer’s disease. Resveratrol also improved the animals’ ability to learn and remember. Since resveratrol can act on all seven of the sirtuins found in mammals and also affects other biological processes (SN Online: 6/28/10), the researchers didn’t know what role, if any, SIRT1 played in the process. To find out, Tsai and her colleagues put mice genetically engineered to lack SIRT1 in their brains through a series of learning and memory tests. The mice had trouble remembering the location of a submerged platform in a water maze, couldn’t tell the difference between a new object and an old one placed in their cages, and did poorly on other memory tests. “The ability for these animals to learn is clearly impaired,” Tsai says. © Society for Science & the Public 2000 - 2010

Keyword: Learning & Memory; Alzheimers
Link ID: 14251 - Posted: 07.13.2010

Mice might turn up their noses at alcohol, but not the prairie vole. This usually upstanding rodent, famous for mating for life and sharing pup-raising duties, apparently likes a stiff drink. “They not only drink alcohol, they prefer it over water,” Allison Anacker, a neuroscience graduate student at Oregon Health & Science University told The Oregonian. Anacker, working under behavioral neuroscience professor Andrey Ryabinin, was looking for a model organism to study some humans’ troubled relationship with alcohol. Mice and rats fail in this role–it’s unusual to find ones that want even a sip of the stuff. In a study published in Addiction Biology last month, Ryabinin’s team records the drunken misadventures of prairie voles. After chugging their preferred 6 percent alcohol drink (about the equivalent of beer), some thirsty voles shoved off parental responsibilities and even walked out on their mates. Though some drank responsibility, others drank to excess, stumbling away from the bar/spiked water bottle. The study suggests that like humans, the voles also make drinking buddies, seemingly encouraging each other to have another. When caged together, the voles appear to match one another drink for drink, a practice that apparently has nothing to do with who’s buying the next round.

Keyword: Drug Abuse
Link ID: 14250 - Posted: 07.13.2010

By GINA KOLATA If you had to choose one public health problem to attack, which would it be: teenage smoking or childhood obesity? To answer that question, you might want to pose another. Who will have the harder road in life, or indeed the longer one: the teenage puffer or the chubby child? Pitting smoking against obesity is tricky because it can mean comparing apples and bonbons, but there is some suggestion that a kind of weird zero-sum game is actually going on. And some smoking opponents fear that a choice has been made — with obesity the winner, quite possibly for the wrong reasons. “Obesity is the new kid on the block, relatively speaking,” said Kenneth E. Warner, dean of the University of Michigan’s school of public health. “Tobacco is old news.” When it comes to smoking, said Stanton A. Glantz, director of the University of California at San Francisco’s Center for Tobacco Control Research and Education, “we really haven’t had anyone pushing it to the top of the agenda.” That is a problem. “It’s not that I am for obesity,” he said, but he finds it less than encouraging, for example, that the hugely influential Robert Wood Johnson Foundation is pulling back from its anti-smoking efforts while directing its money and resources to preventing childhood obesity. Then there is Michelle Obama’s campaign, Let’s Move, to prevent childhood obesity. And in May, the White House Task Force on Childhood Obesity announced its goal — reduce the rate of childhood obesity, now 17 percent, to 5 percent by 2030. Copyright 2010 The New York Times Company

Keyword: Obesity; Drug Abuse
Link ID: 14249 - Posted: 07.12.2010

by Helen Thomson I'VE just had a brainwave. Oh, and there's another. And another! In fact, you will have had thousands of them since you started reading this sentence. These waves of electricity flow around our brains every second of the day, allowing neurons to communicate while we walk, talk, think and feel. Exactly where brainwaves are generated in the brain, and how they communicate information, is something of a mystery. As we begin to answer these questions, surprising functions of these ripples of neural activity are emerging. It turns out they underpin almost everything going on in our minds, including memory, attention and even our intelligence. Perhaps most importantly, haphazard brainwaves may underlie the delusions experienced by people with schizophrenia, and researchers are investigating this possibility in the hope that it will lead to treatments for this devastating condition. So what exactly is a brainwave? Despite the way it is bandied about in everyday chit-chat, the term "brainwave" has a specific meaning in neuroscience, referring to rhythmic changes in the electrical activity of a group of neurons. Each neuron has a voltage, which can change when ions flow in or out of the cell. This is normally triggered by stimulation from another cell, and once a neuron's voltage has reached a certain point, it too will fire an electrical signal to other cells, repeating the process. When many neurons fire at the same time, we see these changes in the form of a wave, as groups of neurons are all excited, silent, then excited again, at the same time. © Copyright Reed Business Information Ltd.

Keyword: Miscellaneous
Link ID: 14248 - Posted: 07.12.2010

By John Cloud Men who cheat on their spouses have always enjoyed an expedient explanation: Evolution made me do it. Many articles (here is one, and here is another), especially in recent years, have explored the theory that men sleep around because evolution has programmed them to seek fertile (and, conveniently, younger) wombs. (See the top 10 political sex scandals.) But what about women? If it's really true that evolution can cause a man to risk his marriage, what effect does it have on women's sexuality? A new journal article suggests that evolutionary forces also push women to be more sexual, although in some unexpected ways. University of Texas psychologist David Buss wrote the article, which appears in the July issue of Personality and Individual Differences, with the help of three grad students, Judith Easton (who is listed as lead author), Jaime Confer and Cari Goetz. Buss, Easton and their colleagues found that women in their 30s and early 40s are significantly more sexual than younger women. Women ages 27 through 45 report not only having more sexual fantasies (and more intense sexual fantasies) than women ages 18 through 26; the older women also report having more sex, period. And they are more willing than younger women to have casual sex, even one-night stands. In other words, despite the girls-gone-wild image of promiscuous college women, it is women in their middle years who are America's most sexually industrious. © 2010 Time Inc.

Keyword: Sexual Behavior; Evolution
Link ID: 14247 - Posted: 07.12.2010

by Susan Heavey and Lisa Richwine WASHINGTON — The first of three new fat-fighting pills faces public scrutiny by U.S. regulatory advisers next week, as small biotechs target the growing number of obese Americans despite a checkered past for weight-loss drugs. Vivus Inc, Arena Pharmaceuticals Inc and Orexigen Therapeutics Inc are trying to succeed where earlier efforts flopped after several weight-loss drugs were linked to serious side effects. The U.S. Food and Drug Administration will seek input from outside advisers July 15 on Vivus' pill, Qnexa, for use with diet and exercise. If approved, it would be the first new prescription weight-loss drug in a decade in the United States, where two out of every three people are overweight. The FDA's review by a panel of outside experts follows a troubled history with obesity pills that either never gained approval, were pulled from the market after sales began, or were slapped with severe warnings. "The history of weight-loss drugs is such that it's a no-brainer that the FDA is going to take each and every one to an advisory panel," said analyst Ira Loss, who follows the agency for Washington Analysis Corp. An advisory panel is one of the last hurdles in a drug's route to market. The FDA will make the final decision, but usually follows the advice of its advisers. Copyright 2010 Reuters

Keyword: Obesity
Link ID: 14246 - Posted: 07.10.2010

Janelle Weaver Birds that spend less time parenting engage more frequently in homosexual behaviour, according to a study published this week. The findings offer a possible explanation for the evolution of homosexuality: parents that devote less time to their offspring have more time and energy to interact with members of the same sex while still producing offspring. Biologists had thought that homosexuality is disadvantageous on an evolutionary level because it distracts animals from pursuing sexual encounters that could result in offspring. Yet more than 130 species of birds participate in homosexual activity — and sometimes a lot of it. In the Laysan albatross (Phoebastria immutabilis), for example, up to 31% of pairs are female–female in some populations, and up to 20% of pairings in graylag geese (Anser anser) are male–male. Scientists have struggled to explain such patterns. But homosexuality may not be costly for birds that have plenty of mating opportunities because of lower parenting demands, says Geoff MacFarlane, an ecologist at the University of Newcastle in Callaghan, Australia. The less effort that females or males put into parental care, the more they participate in homosexual activities, according to a survey of the literature his team published this week in the journal Animal Behaviour1. Vincent Savolainen, a biologist at Imperial College London, says homosexual behaviour is sometimes considered a Darwinian paradox because it does not result in offspring. "This is one of the few studies that explains homosexual behaviour from the evolutionary point of view," he says. © 2010 Nature Publishing Group,

Keyword: Sexual Behavior; Evolution
Link ID: 14245 - Posted: 07.10.2010

By Larry Greenemeier For many, the warm glow of fireflies in the night air is a sure sign that summer has arrived. After dark, these bioluminescent beetles are generally visible only when they emit flashes of yellow, green or pale red from their lower abdomen as part of their mating ritual. Some species of firefly have found their own key to successful coupling— synchronous flashing patterns, a phenomenon that has attracted the attention of a team of researchers studying what pattern recognition tells us about how the brain is wired. To better understand how the brains of humans and other animals process visual signals, Andrew Moiseff, a professor of physiology and neurobiology at the University of Connecticut in Storrs, and Jonathan Copeland, a biology professor at Georgia Southern University in Statesboro, over the past four summers have studied the role that synchronized flashing plays in the mating of the Photinus carolinus species of firefly found in Tennessee's Smoky Mountains National Park.Firefly, bioluminescence, mating In synchronous flashing by P. carolinus fireflies, many males produce flashes simultaneously, rhythmically and repeatedly, according to the researchers, who published their findings in the July 9 issue of Science. These patterns consist of a burst of several flashes (typically six) followed by a period of no flashing that lasts about six-to-eight seconds. During these pauses, the female responds with two flashes in rapid succession, with the second flash beginning almost immediately after the first one is finished. The female may produce one to four of these "doublets" while perched on leaves or branches, says Moiseff, the study's lead author. © 2010 Scientific American,

Keyword: Sexual Behavior; Evolution
Link ID: 14244 - Posted: 07.10.2010

by Linda Geddes, Amsterdam THE discovery of an antibody that binds to certain brain receptors could reduce the side effects of a common stroke drug and buy additional time in which to use it. The preferred treatment for ischaemic stroke, in which a blood clot cuts off the blood supply to brain tissue, is a drug called rtPA, which dissolves the clot. However, that drug has to be given within the first few of hours of a stroke, otherwise the risks of treatment outweigh the benefits. Dissolving the clot can lead to a sudden rise in blood pressure, increasing the chance that a blood vessel will rupture and bleed into the brain. Only 5 to 10 per cent of people who suffer a stroke make it to hospital early enough to be treated with rtPA, says Denis Vivien of the University of Caen Basse-Normandie in France. The rest are given drugs that do not destroy the initial clot but reduce the chance of further clots forming. One reason for a delay in administering rtPA is that a brain scan must be carried out to determine the nature of the stroke. People with haemorrhagic stroke, in which a blood vessel in the brain bursts, should not receive rtPA as it increases the risk of bleeding. Now a startling discovery by Vivien has put a different perspective on this relatively simple picture: rtPA is actually released by brain cells. "This was completely unexpected," he says. © Copyright Reed Business Information Ltd.

Keyword: Stroke
Link ID: 14243 - Posted: 07.10.2010

by Andy Coghlan A GENE has been discovered that appears to dictate the sexual preferences of female mice. Delete the gene and the modified mice reject the advances of the males and attempt to mate with other females instead. While it is impossible to say whether the finding has any relevance for human sexuality, it provides a clue as to how sexuality develops in mammals. Chankyu Park and colleagues at the Korea Advanced Institute of Science and Technology in Daejon, South Korea, deleted the FucM gene in mouse embryos to see what effect it would have on behaviour. Female mice lacking the gene avoided the advances of males, stopped sniffing male urine and attempted to mate with other females, though their ability to have pups was unaffected (BMC Genetics, DOI: 10.1186/1471-2156-11-62). The gene the team deleted is for an enzyme called fucose mutarotase, which adds the sugar fucose to proteins. Park believes that disabling the gene exposes parts of the developing mouse brain linked with sexual preference in adult life to extra oestrogen. The hormone masculinises the brain in mice - though not in people. In a normal female mouse fetus, this extra oestrogen would be "filtered out" by a substance called alpha-fetoprotein. But AFP only functions properly when adorned with fucose. So without the gene that makes the enzyme, AFP cannot keep the flood of oestrogen at bay. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior
Link ID: 14242 - Posted: 07.10.2010