by Helen Thompson It's no secret that some plants lace their nectar with caffeine in an effort to attract more pollinators, and that buzz sticks around in a bee's memory. These caffeinated flowers lure naive honeybees to return over and over again — and bring their friends, researchers report October 15 in Current Biology. When feeding off caffeinated nectar (versus noncaffeinated nectar), honeybees increased their foraging activity and performed four times as many waggle dances to alert other workers to food sources. Though bees might be more persistent foragers while under the influence of caffeine, they focused mainly on caffeinated sources instead casting a broad search. Plants may also substitute caffeine for sugar, the researchers note, duping bees into gathering nectar that's less valuable for honey production. © Society for Science & the Public 2000 - 2015.

Keyword: Drug Abuse; Evolution
Link ID: 21515 - Posted: 10.16.2015

Kerri Smith Scientists have discovered two extra neurons in a worm species that — they thought — already had its entire nervous system mapped. “It is a bit of a shock,” says Richard Poole, a developmental biologist at University College London (UCL), and one of the team that found the neurons by accident. The researchers call them mystery cells of the male, or MCMs, because they are found only in male nematode worms. The neurons help the worms learn when to prioritize mating over eating, revealing how a seemingly simple brain can be capable of a complex learned behaviour — and one that differs between the sexes. Caenorhabditis elegans worms are the model animal of choice for many neuroscientists, because their neural circuits are so simple that they can be mapped in full. They have two sexes: hermaphrodite and male. Hermaphrodites, the best studied, have just 302 neurons, but males have more — the MCMs raise their total to 385 neurons1. The two ‘mystery’ cells were discovered when Poole’s colleague at UCL, Arantza Barrios, was looking at the distribution of a peptide often found in neurons, called pdf-1. She saw cells light up where she thought they should not — near the worm’s nose. The neurons develop when male worms reach maturity, the researchers worked out. Their report is published in Nature1. Sex or food? © 2015 Nature Publishing Group,

Keyword: Sexual Behavior; Development of the Brain
Link ID: 21514 - Posted: 10.15.2015

By Nicholas Bakalar Physical therapy may provide little relief for recent-onset low back pain, a small randomized trial has found. The study, published in JAMA, included 207 men and women, average age 37, with a score of 20 or higher on a widely used 100-point scale that quantifies disability from low back pain. The study included people with recent-onset pain who were assigned to one of two groups. The first received four sessions of exercise and manipulation under the guidance of a trained physical therapist. Those in the other group were told that low back pain usually gets better, and were advised to be as active as possible. There were no significant differences at any time in pain intensity, quality of life or the number of visits to health care providers. Compared with the usual care group, the physical therapy group did show significant improvement on the disability scale after three months. But after one year, there was no difference between the two groups in this measure either. “Most treatments that are effective have only modest effects,” said the lead author, Julie M. Fritz, a professor in the department of physical therapy at the University of Utah. “The pattern of low back pain is one of recurrence and remission, and changing that pattern is a real challenge. There are no magic answers.” © 2015 The New York Times Company

Keyword: Pain & Touch
Link ID: 21513 - Posted: 10.15.2015

By AUSTIN RAMZY HONG KONG — Australian officials have responded to criticism from animal rights activists and celebrities, including the former actress Brigitte Bardot and the singer Morrissey, that a government plan to protect threatened species by killing millions of feral cats is unnecessarily cruel. Gregory Andrews, Australia’s threatened species commissioner, has written open letters to Ms. Bardot and Morrissey saying that feral cats prey on more than 100 of the country’s threatened species and that they were a “major contributor” to the extinction of at least 27 mammal species in the country over the past 200 years. He called some of the extinct species, such as the lesser bilby, desert bandicoot, crescent nailtail wallaby and big-eared hopping mouse, “delightful creatures, rich in importance in Australian indigenous culture, and formerly playing important roles in the ecology of our country. We don’t want to lose any more species like these.” The Australian Department of the Environment says that feral cats are the biggest threat to the country’s mammals, ahead of foxes and habitat loss. The government plan would use poison and traps to kill the cats. In announcing the plan in July, Greg Hunt, the environment minister, said that he wanted two million feral cats culled by 2020. Australia has an estimated 20 million feral cats, which are an invasive species brought by European settlers. Calls to exterminate the cats have been floated before, including one in the 1990s that called for killing all feral cats by 2020. © 2015 The New York Times Company

Keyword: Animal Rights
Link ID: 21512 - Posted: 10.15.2015

by Bethany Brookshire It’s happened to all of us at one time or another: You’re walking through a crowd, and suddenly a face seems incredibly familiar — so much so that you do a double-take. Who is that? How do you know them? You have no idea, but something about their face nags at you. You know you’ve seen it before. The reason you know that face is in part because of your perirhinal cortex. This is an area of the brain that helps us to determine familiarity, or whether we have seen an object before. A new study of brain cells in this area finds that firing these neurons at one frequency makes the brain treat novel images as old hat. But firing these same neurons at another frequency can make the old new again. “Novelty and familiarity are both really important,” says study coauthor Rebecca Burwell, a neuroscientist at Brown University in Providence, R.I. “They are important for learning and memory and decision making.” Finding a cache of food and knowing it is new could be useful for an animal’s future. So is recognizing a familiar place where the pickings were good in the past. But knowing that something is familiar is not quite the same thing as knowing what that thing is. “You’re in a crowd and you see a familiar face, and there’s a feeling,” Burwell explains. “You can’t identify them, you don’t know where you met them, but there’s a sense of familiarity.” It’s different from recalling where you met the person, or even who the person is. This is a sense at the base of memory. And while scientists knew the perirhinal cortex was involved in this sense of familiarity, how that feeling of new or old was coded in the brain wasn’t fully understood. © Society for Science & the Public 2000 - 2015

Keyword: Attention
Link ID: 21511 - Posted: 10.14.2015

Gene therapy preserved vision in a study involving dogs with naturally occurring, late-stage retinitis pigmentosa, according to research funded by the National Eye Institute (NEI), part of the National Institutes of Health. The findings contribute to the groundwork needed to move gene therapy forward into clinical trials for people with the blinding eye disorder, for which there is currently no cure. Scientists from the University of Pennsylvania and the University of Florida, Gainesville also determined for the first time that gene therapy may be of potential benefit even after there has been significant loss of cells in the eye. Up to this point, animal studies had shown benefits from gene therapy only when it was used in the earliest stages of the disease. “The study shows that a corrective gene can stop the loss of photoreceptors in the retina, and provides good proof of concept for gene therapy at the intermediate stage of the disease, thus widening the therapeutic window,” said Neeraj Agarwal, Ph.D., a program director at NEI. Retinitis pigmentosa is the most common inherited disease that causes degeneration of the retina, the light-sensitive tissue lining the back of the eye. Roughly 1 in 4,000 people are affected and about 10 to 20 percent have a particularly severe form called X-linked retinitis pigmentosa, which predominately affects males, causing night blindness by age 10 and progressive loss of the visual field by age 45. About 70 percent of people with the X-linked form carry mutations that cause loss of function of the retinitis pigmentosa GTPase Regulator (RPGR) gene, which encodes a protein important for maintaining the health of photoreceptors.

Keyword: Vision
Link ID: 21510 - Posted: 10.14.2015

By Gretchen Reynolds Can a shot of salt water make you a faster runner? The answer appears to be a resounding yes, if you believe that the salt water contains something that should make you a faster runner, according to a new study of the power of placebos in athletic performance. Anyone who exercises knows from experience that our minds and mental attitudes affect physical performance. Who hasn’t faced a moment when, tiring at the end of a strenuous workout or race, we are about to quit before suddenly being passed on the path or shown up in the gym by someone we know we should outperform, and somehow we find an extra, unexploited gear and spurt on? This phenomenon is familiar to physiologists, many of whom believe that our brains, in order to protect our bodies, send out signals telling those bodies to quit before every single resource in our muscles and other tissues is exhausted. We think we are at the outer limits of our endurance or strength, when, in reality, we may still have a physical reserve available to us, if we can find a way to tap it. Past studies have shown that lying to people is one way to exploit that reserve. Telling athletes that they are moving slower than in fact they are, for instance, often results in their speeding up past the pace that they thought they could maintain. Or give them a sugar pill that they think contains caffeine or steroids and they will run more swiftly or lift more weight than before. But none of these studies tested the effects of placebos and deception in relatively real-world competitive situations, which have their own effects on mental responses. People are almost always faster during competitive races than in training, studies show, even when they are trying to replicate race pace. © 2015 The New York Times Company

Keyword: Pain & Touch
Link ID: 21509 - Posted: 10.14.2015

By Christopher Intagliata If you're lost, you need a map and a compass. The map pinpoints where you are, and the compass orients you in the right direction. Migratory birds, on the other hand, can traverse entire hemispheres and end up just a couple miles from where they bred last year, using their senses alone. Their compass is the Sun, the stars and the Earth's magnetic field. But their map is a little more mysterious. One theory goes that they use olfactory cues—how a place smells. Another is that they rely on their sense of magnetism. Researchers in Russia investigated the map issue in a past study by capturing Eurasian reed warblers on the Baltic Sea as they flew northeast towards their breeding grounds near Saint Petersburg. They moved the birds 600 miles east, near Moscow. And the birds just reoriented themselves to the northwest—correctly determining their new position. Now the same scientists have repeated that experiment—only this time, they didn't move the birds at all. They just put them in cages that simulated the magnetic field of Moscow, while still allowing the birds to experience the sun, stars and smells of the Baltic. Once again, the birds re-oriented themselves to the northwest—suggesting that the magnetic field alone—regardless of smells or other cues, is enough to alter the birds' mental map. The study is in the journal Current Biology. [Dmitry Kishkinev et al, Eurasian reed warblers compensate for virtual magnetic displacement] And if you're envious of that sixth sense—keep in mind that since the Earth's magnetic field fluctuates, the researchers say magnetic route-finding is best for crude navigation. Meaning for door-to-door directions—you’re still better off with your GPS. © 2015 Scientific American,

Keyword: Animal Migration
Link ID: 21508 - Posted: 10.14.2015

By Martin Enserink Researchers who conduct animal studies often don't use simple safeguards against biases that have become standard in human clinical trials—or at least they don't report doing so in their scientific papers, making it impossible for readers to ascertain the quality of the work, an analysis of more than 2500 journal articles shows. Such biases, conscious or unconscious, can make candidate medical treatments look better than they actually are, the authors of the analysis warn, and lead to eye-catching results that can't be replicated in larger or more rigorous animal studies—or in human trials. Neurologist Malcolm MacLeod of the Centre for Clinical Brain Sciences at the University of Edinburgh and his colleagues combed through papers reporting the efficacy of drugs in eight animal disease models and checked whether the authors reported four measures that are widely acknowledged to reduce the risk of bias. First, if there was an experimental group and a control group, were animals randomly assigned to either one? (This makes it impossible for scientists to, say, assign the healthiest mice or rats to a treatment group, which could make a drug look better than it is.) Second, were the researchers who assessed the outcomes of a trial—for instance, the effect of a treatment on an animal's health—blinded to which animal underwent what procedure? Third, did the researchers calculate in advance the sample size needed to show that they didn't just accumulate data until they found something significant? And finally, did they make a statement about their conflicts of interest? © 2015 American Association for the Advancement of Science

Keyword: Animal Rights; Attention
Link ID: 21507 - Posted: 10.14.2015

Rachel Ehrenberg Patterns of neural circuitry in the brain's frontal and parietal lobes can be used to distinguish individuals on the basis of their brain scans. Our brains are wired in such distinctive ways that an individual can be identified on the basis of brain-scan images alone, neuroscientists report. In a study published in Nature Neuroscience1 on 12 October, researchers studied scans of brain activity in 126 adults who had been asked to perform various cognitive tasks, such as memory and language tests. The data were gathered by the Human Connectome Project, a US$40-million international effort that aims to map out the highways of neural brain activity in 1200 people. To study connectivity patterns, researchers divided the brain scans into 268 regions or nodes (each about two centimetres cubed and comprising hundreds of millions of neurons). They looked at areas that showed synchronized activity, rather like discerning which instruments are playing together in a 268-piece orchestra, says Emily Finn, a co-author of the study and a neuroscience PhD student at Yale University in New Haven, Connecticut. In some regions of the brain — such as those that involve networks controlling basic vision and motor skills — most people’s neural circuitry connects up in similar ways, the team found. But patterns of connectivity in other brain regions, such as the frontal lobes, seem to differ between individuals. The researchers were able to match the scan of a given individual's brain activity during one imaging session to the same person’s brain scan taken at another time — even when that person was engaged in a different task in each session. © 2015 Nature Publishing Group

Keyword: Brain imaging
Link ID: 21506 - Posted: 10.13.2015

By ERICA GOODE Women who suffer from anorexia are often thought of as having an extraordinary degree of self-control, even if that discipline is used self-destructively. But a new study suggests that the extreme dieting characteristic of anorexia may instead be well-entrenched habit — behavior governed by brain processes that, once set in motion, are inflexible and slow to change. The study’s findings may help explain why the eating disorder, which has the highest mortality rate of any mental illness, is so stubbornly difficult to treat. But they also add to increasing evidence that the brain circuits involved in habitual behavior play a role in disorders where people persist in making self-destructive choices no matter the consequences, like cocaine addiction or compulsive gambling. In the case of anorexia, therapists often feel helpless to interrupt the relentless dieting that anorexic patients pursue. Even when patients say they want to recover, they often continue to eat only low-fat, low-calorie foods. Neither psychiatric medications nor talk therapies that are used successfully for other eating disorders are much help in most cases. And research suggests that 50 percent or more of hospitalized anorexic patients who are discharged at a normal weight will relapse within a year. “The thing about people with anorexia nervosa is that they can’t stop,” said Dr. Joanna E. Steinglass, an associate professor in clinical psychiatry at the New York State Psychiatric Institute at Columbia University Medical Center and a co-author of the new study, which appears in the journal Nature Neuroscience. “They come into treatment saying they want to get better, and they can’t do it,” Dr. Steinglass added. Karin Foerde, a research scientist at the psychiatric institute and Columbia, was the lead author on the study. © 2015 The New York Times Company

Keyword: Apoptosis; Attention
Link ID: 21505 - Posted: 10.13.2015

By Nancy Szokan Sensory deprivation is Sushma Subramanian’s topic in the October issue of Women’s Health magazine, and she offers a couple of extreme examples. Julie Malloy, 33, from York, Pa., describes living without the sense of touch: “I was born with a rare sensory illness that leaves me unable to feel pain, temperature, deep pressure, or vibrations in my arms, legs, and the majority of my chest and back. I use vision to compensate as much as I can. . . . “I always wash my face with cold water; I once burned myself without realizing it. . . . When I drive, I can’t really tell how hard I’m pushing on the pedals. I watch others really enjoy it when someone kisses their arm or get tingly when someone hugs them, but I can’t even feel anything during sex.” Erin Napoleone, 31, from Havre de Grace, Md., describes losing her sense of smell: “As a teen, I was in a car accident. A few days later, I watched my father make homemade tomato sauce — but I didn’t smell a thing. Then I couldn’t detect my mom’s familiar perfume. A head CT scan confirmed my sense of smell was gone for good.” The magazine points out that some senses naturally deteriorate with age and that taking care of your skin — say, by keeping it moisturized and protecting it from damage — can help preserve the sense of touch. But olfactory nerves facing “prolonged exposure to rank odors (think freeway fumes or curbside trash)” can be permanently damaged.

Keyword: Pain & Touch; Chemical Senses (Smell & Taste)
Link ID: 21504 - Posted: 10.13.2015

By SINDYA N. BHANOO Tiny nematode worms called Caenorhabditis elegans have a peculiar reproductive story: Most females are hermaphrodites that make sperm, self-fertilize and produce more hermaphrodites. Males are few, and are known to mate with each other. Now, a new study reports that a variation in a single gene results in male worms with excretory pores that attract the sexual attentions of other males. “Other males copulate with this excretory pore, located on the neck,” said Matthew Rockman, a biologist at New York University. He and his colleagues reported their findings in the journal Current Biology. Although male worms are rare in the wild, they are easily bred in the laboratory. Researchers report that the gene variant, known as plep-1, may somehow be altering the chemical profile of the excretions in a way that makes them more attractive to other males. Copulation often does not work out well for the male that is approached, Dr. Rockman said. Males that mate with the excretory pore of another male usually leave behind a plug that weakens the worm and reduces life expectancy. Hermaphrodites with the variation of the same gene also have a lower life expectancy and do not reproduce as well. Next, the researchers want to learn what it is about a mutation in the plep-1 gene that makes males attractive to other males. © 2015 The New York Times Company

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 21503 - Posted: 10.13.2015

Ed Yong This week, a team from the University of California, Los Angeles claimed to have found several epigenetic marks—chemical modifications of DNA that don’t change the underlying sequence—that are associated with homosexuality in men. Postdoc Tuck Ngun presented the results yesterday at the American Society of Human Genetics 2015 conference. Nature News were among the first to break the story based on a press release issued by the conference organisers. Others quickly followed suit. “Have They Found The Gay Gene?” said the front page of Metro, a London paper, on Friday morning. Meanwhile, the mood at the conference has been decidedly less complimentary, with several geneticists criticizing the methods presented in the talk, the validity of the results, and the coverage in the press. Ngun’s study was based on 37 pairs of identical male twins who were discordant—that is, one twin in each pair was gay, while the other was straight—and 10 pairs who were both gay. He analysed 140,000 regions in the genomes of the twins and looked for methylation marks—chemical Post-It notes that dictate when and where genes are activated. He whittled these down to around 6,000 regions of interest, and then built a computer model that would use data from these regions to classify people based on their sexual orientation. The best model used just five of the methylation marks, and correctly classified the twins 67 percent of the time. “To our knowledge, this is the first example of a biomarker-based predictive model for sexual orientation,” Ngun wrote in his abstract. The problems begin with the size of the study, which is tiny. The field of epigenetics is littered with the corpses of statistically underpowered studies like these, which simply lack the numbers to produce reliable, reproducible results.

Keyword: Sexual Behavior; Epigenetics
Link ID: 21502 - Posted: 10.13.2015

By ANDREW SOLOMON INEXPLICABLE violence is the hardest kind to accept. The human wish to insert logic where there is none often drives bystanders to psychic violence of their own. This happened again last week, after it was reported that the shooter at Umpqua Community College in Oregon, Christopher Harper-Mercer, who killed nine people and injured several others, may have been autistic. Although there is no established connection between autism and murder, some eagerly leapt to causality and scapegoating. The killer’s “diagnosis” was based primarily on posts on Yahoo made over the last decade by his mother, Laurel Harper, in which she characterized both herself and her son as having Asperger’s syndrome — a category no longer in medical use that describes autistic people with advanced verbal skills. Mr. Harper-Mercer attended a school that caters to children with special needs, including autism. While Ms. Harper is not a doctor, her descriptions of her son across his childhood are consistent with the syndrome. A Facebook page called “Families Against Autistic Shooters” ranted about “the soulless, dead eyes of autistic children,” and characterized them as “cold, calculating killing machines with no regard for human life!” Its author announced: “What do all shooters over the last few years have in common? A lack of empathy and compassion due to Autism!” If Mr. Harper-Mercer were rumored to have been diabetic or afflicted with male-pattern baldness, no such “explanations” of his behavior would have surfaced. But despite a huge increase in awareness of autism among the public, those with the condition are often subject to this type of disparagement. This was evident in both the Facebook page and the response to it by Facebook’s management, who, despite the site’s anti-bullying policy, initially refused to remove it on grounds that it did not target named individuals. “Families Against Autistic Shooters” remained accessible until last Monday, by which time escalating media attention and a petition on Change.org with nearly 5,000 signatures embarrassed administrators into action. For the time it was viewable, the page stigmatized a population far more likely to be attacked than to attack, far less likely to receive justice when injured, and far more likely to be misunderstood. © 2015 The New York Times Company

Keyword: Autism; Aggression
Link ID: 21501 - Posted: 10.12.2015

By Kat Long In the delivery room, the (slight) odds are that a newborn is a baby boy, not a girl. Males make up 51.3 percent of live births in the U.S., a rate that has remained about constant for the past seven decades. Experts assumed that this male-skewed sex ratio began at conception, but a new analysis of fetal records shows that the chances overall of finding a boy or a girl start out at 50–50 and change over the course of pregnancy—leaning female, then male, then female again as nine months pass. In the most comprehensive study of its kind to date, biologist Steven Hecht Orzack of the Fresh Pond Research Institute in Massachusetts and his collaborators analyzed roughly 36 million fertility treatment records, prenatal tests, induced abortions and U.S. Census data points. They discovered several nodes at which the sex ratio wavered from 50–50. Those vacillations most likely arise because of genetic and chromosomal abnormalities that cause natural abortions at various stages of gestation, write the study's authors in the Proceedings of the National Academy of Sciences USA. “This is basic knowledge about human pregnancy that we didn't have before,” Orzack says. “Demographers, developmental biologists, and many more can all get something out of this study.” © 2015 Scientific American

Keyword: Sexual Behavior
Link ID: 21500 - Posted: 10.12.2015

By KENNETH D. MILLER SOME hominid along the evolutionary path to humans was probably the first animal with the cognitive ability to understand that it would someday die. To be human is to cope with this knowledge. Many have been consoled by the religious promise of life beyond this world, but some have been seduced by the hope that they can escape death in this world. Such hopes, from Ponce de León’s quest to find a fountain of youth to the present vogue for cryogenic preservation, inevitably prove false. In recent times it has become appealing to believe that your dead brain might be preserved sufficiently by freezing so that some future civilization could bring your mind back to life. Assuming that no future scientists will reverse death, the hope is that they could analyze your brain’s structure and use this to recreate a functioning mind, whether in engineered living tissue or in a computer with a robotic body. By functioning, I mean thinking, feeling, talking, seeing, hearing, learning, remembering, acting. Your mind would wake up, much as it wakes up after a night’s sleep, with your own memories, feelings and patterns of thought, and continue on into the world. I am a theoretical neuroscientist. I study models of brain circuits, precisely the sort of models that would be needed to try to reconstruct or emulate a functioning brain from a detailed knowledge of its structure. I don’t in principle see any reason that what I’ve described could not someday, in the very far future, be achieved (though it’s an active field of philosophical debate). But to accomplish this, these future scientists would need to know details of staggering complexity about the brain’s structure, details quite likely far beyond what any method today could preserve in a dead brain. © 2015 The New York Times Company

Keyword: Robotics; Consciousness
Link ID: 21499 - Posted: 10.12.2015

The month of your birth influences your risk of developing dementia. Although the effect is small compared to risk factors such as obesity, it may show how the first few months of life can affect cognitive health for decades to come. Demographers Gabriele Doblhammer and Thomas Fritze from the University of Rostock, Germany, studied data from the Allgemeine Ortskrankenkasse – Germany’s largest public health insurer – for nearly 150,000 people aged 65 and over. After adjusting for age, they found that those born in the three months from December to February had a 7 per cent lower risk of developing dementia than those born in June to August, with the risk for other months falling in between. There’s nothing astrological about the effect, however. Instead, birth month is a marker for environmental conditions such as weather and nutrition, says Gerard van den Berg, an economist at the University of Bristol, UK, who studies the effects of economic circumstances on health. Summer-born babies are younger when they face the respiratory infections of their first winter, for example. And in the past, babies born in spring and summer would have been in late gestation when the supply of fresh fruit and vegetables from the autumn harvest would have largely run out. Pollution from wood fires or coal heating might also have played a role. There’s evidence from other studies that such factors can have lifelong effects on metabolism and the immune system, increasing the risk of conditions such as diabetes, obesity and high blood pressure. Doblhammer and Fritze’s results show this is true for dementia too. © Copyright Reed Business Information Ltd.

Keyword: Biological Rhythms; Alzheimers
Link ID: 21498 - Posted: 10.10.2015

By Ariana Eunjung Cha When it comes to studies on birth order, first-borns tend to make out pretty well. Research says they tend to be smarter, more outgoing, and exhibit more leadership qualities. Unfortunately, it's not all good news. A new paper published in JAMA Ophthalmology shows that first-borns also tend to be 10 percent more likely to be near-sighted and 20 percent more likely to have severe myopia than their siblings. In fact, the risk for myopia appeared to be progressively lower the later you were born in terms of your birth order. The researchers from Cardiff University suggested that the cause was “parental investment in education” because parents may have a tendency to put more pressure on first-borns. They theorized that parents may be more demanding that first-borns do more "near" activities, such as reading, which may impact their eyesight. Previous studies have shown a strong link between time spent outdoors and a diminished risk of myopia, and it may stand to reason that children who spend more time on studies may be spending less time outdoors. Jeremy Guggenheim, a doctoral student, and colleagues wrote that while there's no way to make a definitive causal link, their study found that when they adjusted for a proxy for educational exposure — the highest educational degree or age at completion of full-time education — they saw a less dramatic association between near-sightedness and birth order.

Keyword: Vision
Link ID: 21497 - Posted: 10.10.2015

By Bill Berkrot (Reuters) - U.S. researchers on Thursday said they had found a way to predict male sexual orientation based on molecular markers that control DNA function, but genetics experts warned that the research has important limitations and will not provide definitive answers to a potential biological basis for sexual preference. Findings from the study, which has yet to be published or reviewed in detail by other scientists, were presented at a meeting of the American Society of Human Genetics in Baltimore. It followed 37 pairs of identical male twins in which one was homosexual and one heterosexual, and 10 sets of twins in which both males were homosexual. The study found that the presence of specific epigenetic marks in nine areas of the human genome could predict homosexual preference with up to 70% accuracy. The epigenome is sometimes described as molecular "switches" that can turn on or silence individual genes in DNA. Scientists believe epigenetic differences can be influenced by environmental and lifestyle factors, from exposure to chemicals to parental nurturing. "To our knowledge, this is the first example of a predictive model for sexual orientation based on molecular markers," Tuck Ngun, lead researcher on the study from the David Geffen School of Medicine of the University of California, Los Angeles, said in a statement. Genetics experts who critiqued the findings said it was premature to draw any conclusions on the predictive powers of epigenetic markers. © 2015 Scientific American

Keyword: Sexual Behavior; Epigenetics
Link ID: 21496 - Posted: 10.10.2015