'Genes, environment influence each other'

Recent studies of social creatures like birds and bees show that interaction between genes and behaviour is a two-way street.

Genes in the brain are malleable, turning on or off in response to internal and external cues. While genetic variation influences brain function and social behaviour, social information also alters gene expression in the brain to influence behaviour, write the study's authors, Gene Robinson of the University of Illinois, Stanford University biology professor Russell Fernald and Illinois cell and developmental biology and neuroscience professor David Clayton.

Thanks to the newly sequenced genomes of several social animals, including honey bees and zebra finches and new technologies like microarrays (glimpsing activity of thousands of genes at a time), neuroscientists are gradually coming to understand that "there is a dynamic relationship between genes and behaviour", Robinson said.

A critical insight came in 1992, in a study of songbirds led by Clayton. He and colleagues found that expression of a specific gene increases in the forebrain of a zebra finch or canary just after it hears a new song from a male of the same species. This gene, egr1, codes for a protein that itself regulates the expression of other genes.

The finding was not unprecedented; previous studies had shown that genes switch on and off when an animal is trained to perform a task in the lab, Robinson said, says a University of Illinois statement.

But when Clayton's team found this change in gene expression in response to a social signal - a song from a potential competitor, something the bird would likely hear in nature - it drew attention to how powerfully social interactions can alter gene expression in the brain.

"What's more significant to a bird than hearing another bird singing?" Clayton said. "This is going on in the equivalent of our auditory cortex and association cortex, so this is pretty high-level stuff going on in the brain. And this was happening in more or less real time by very naturalistic stimuli."

Reading Clayton's 1992 paper "was a eureka moment for me", Robinson said.

In his own work, Robinson has used microarrays to study this phenomenon on a larger scale and has found that literally thousands of genes turn on or off in the honey bee brain in response to social stimuli.

These findings were published this week in Science.

Last updated on Nov 7^th, 2008 at 15:35 pm IST--IANS