Genetic way to tame Casanovas

Emory University press release

Yerkes and CBN Researchers Make Promiscuous Animals Monogamous by Manipulating Genes

Researchers at the Yerkes National Primate Research Center of Emory University and Atlanta's Center for Behavioral Neuroscience (CBN) have found transferring a single gene, the vasopressin receptor, into the brain's reward center makes a promiscuous male meadow vole monogamous. This finding, which appears in the June 17 issue of Nature, may help better explain the neurobiology of romantic love as well as disorders of the ability to form social bonds, such as autism. In addition, the finding supports previous research linking social bond formation with drug addiction, also associated with the reward center of the brain.

In their study, Yerkes and CBN post-doctoral fellow Miranda M. Lim, PhD, and Yerkes researcher Larry J. Young, PhD, of the Department of Psychiatry and Behavioral Sciences at Emory University's School of Medicine and the CBN, attempted to determine whether differences in vasopressin receptor levels between prairie and meadow voles could explain their opposite mating ehaviors. Previous studies of monogamous male prairie voles, which form lifelong social or pair bonds with a single mate, determined the animals' brains contain high levels of vasopressin receptors in one of the brain's principal reward regions, the ventral pallidum. The comparative species of vole, the promiscuous meadow vole, which frequently mates with multiple partners, lacks vasopressin receptors in the ventral pallidum.

The scientists used a harmless virus to transfer the vasopressin receptor gene from prairie voles into the ventral pallidum of meadow voles, which increased vasopressin receptors in the meadow vole to prairie-like levels. The researchers discovered, just like prairie voles, the formerly promiscuous meadow voles then displayed a strong preference for their current partners rather than new females. Young acknowledges many genes are likely involved in regulating lifelong pair bonds between humans. "Our study, however, provides evidence, in a comparatively simple animal model, that changes in the activity of a single gene profoundly can change a fundamental social behavior of animals within a species."

According to previous research, vasopressin receptors also may play a role in disorders of the ability to form social bonds, such as in autism. "It is intriguing," says Young, "to consider that individual differences in vasopressin receptors in humans might play a role in how differently people form relationships."

And, Lim adds, past research in humans has shown the same neural pathways involved in the formation of romantic relationships are involved in drug addiction. "The brain process of bonding with one's partner may be similar to becoming addicted to drugs: both activate reward circuits in the brain." The researchers' next step is to determine why there is extensive variability in behaviors among individuals within a species in order to better understand the evolution of social behavior.

The Yerkes National Primate Research Center of Emory University is one of eight National Primate Research Centers funded by the National Institutes of ealth. The Yerkes Research Center is a multidisciplinary research institute recognized as a leader in biomedical and behavioral studies with nonhuman primates and rodents. Yerkes scientists are on the forefront of developing vaccines for AIDS and malaria, and treatments for cocaine addiction and Parkinson's disease.

The Center for Behavioral Neuroscience, a National Science Foundation Science and Technology Center consisting of more than 90 neuroscientists at eight metro Atlanta colleges and universities, conducts research on the basic neurobiology of complex social behaviors. Its programs have led to a breakthrough treatment for anxiety-related disorders and new understanding of the potential roles of the neurochemicals vasopressin and oxytocin in autism.

(Source: Emory University Press Release)

Humans, chimps almost a match

USA Today

31^st August, 2005

Clint the chimpanzee, whose genome sequence appears in 'Nature,' helped show there's little difference between man and ape.

Yerkes National Primate Research Center, AFP/Getty Images

By Steve Sternberg, USA TODAY

Humans and chimpanzees share an almost identical genetic inheritance, scientists report Thursday in a landmark comparison that they call an "elegant confirmation" of Charles Darwin's theory of evolution Although scientists have long believed that humans and chimps are related, this comprehensive analysis of their separate genomes offers the best proof of their shared genetic past.

The 3 billion genetic letters in the two genetic blueprints are 96% identical with just 40 million differences, the researchers report in the journal Nature.

By delving more deeply into those differences, researchers hope to explain why humans are susceptible to certain diseases; why our evolutionary paths diverged from ancestral chimps 6 million years ago; and, on an even more basic level, what makes us human.

"We can peek into evolution's lab notebook and see what went on there," says Francis Collins, director of the National Human Genome Research Institute.

The analysis offers clues to the cause of diseases such as Alzheimer's and to why chimps and humans are susceptible to different diseases.

"Evolutionary analysis is a handmaiden to human medicine," says Eric Lander of the Broad Institute of the Massachusetts Institute of Technology and Harvard.

For example, in a discovery that could offer insights into Alzheimer's, researchers found mutations that turn off the human caspase-12 gene, which causes damaged cells to self-destruct. Those mutations weren't found in chimps, which aren't as susceptible to Alzheimer's. Knocking out caspase-12 in mice makes their brain cells more likely to survive with Alzheimer's-like damage.

Researchers also identified mutations in humans that were important for survival, including a gene associated with speech and a gene that ramps up response to sugar, an advantage in lean times but a potential ticket to diabetes today.

"Reading these two genomes side by side, it's amazing to see the evolutionary changes that are occurring," says Robert Waterston of the University of Washington. "I couldn't imagine Darwin looking for stronger confirmation of his theories."

Chimpanzees score high in conformist behaviour

Hindustan Times, New Delhi, Monday, August 22, 2005

Learning from others and doing the same as your group or society may be a tendency not restricted to humans, with new psychological research revealing socially conformist behaviour in chimpanzees, the science magazine Nature reported on Sunday.

Andrew Whiten of the St Andrews University of Scotland and the University of Emory in Atlanta in the United States and his colleagues made this finding after studying three groups of chimpanzees at the Yerkes National Primate Research Centre in Atlanta.

For two of the groups, they privately taught several high-ranking females to use different methods to extract a morsel of food from a feeding apparatus made up of a series of tubes and blocked by a stopper.

The leading female, Erika, in the first group was taught the "poking method" where she used a stick to push the stopper towards the end of the tube to make the fruit fall into another smaller interior tube and roll out.

A second group, led by Georgia, was taught to obtain the fruit with the "lifting method" where the stopper could be lifted out by putting the stick in a hook which also made the fruit fall out.

A third control group was given no training by humans in either technique.

The researchers then allowed each chimpanzee group access to the feeding apparatus. The other chimps observed their senior female's technique and were generally quick to copy, showing that they can learn skills in the absence of direct human tuition.

The "poke" method was more effective as several members of the "lift" group independently discovered and adopted the "poke" technique. But, despite this, the "lift" group retained its overall bias towards the "lift" technique.

The third group, who had no single "teacher" in their group, failed to resolve the problem of how to obtain the food from the apparatus.

Whiten and his colleagues, Victoria Horner and Frans de Waal, said this result showed chimpanzees copy those in their group and in this way develop "cultural" traditions, suggesting that social conformity in humans has ancient evolutionary roots.