Science has turned to chickens to find out why some people are chickens.
Researchers have analysed the DNA of hybrid fowl in an effort to track down genes that cause anxiety.
The study, published this morning in the journal Genetics, could cast light on inherited traits that make some people confident and cocky while others are coy and cowardly.
It could also help explain why diseases closely related to anxiety tend to run in the family.
Lead researcher Dominic Wright, of Linkoping University in Sweden, said studies into genetic influences on behaviour mainly focused on mental health disorders.
“But what about more subtle differences in behaviour?” he said. “For example, what makes one person a little more anxious than others? And what makes someone else a little bolder?
“Animal models like the chicken allow us to address questions like these using controlled breeding experiments.”
The team crossbred domestic chickens with a species of their wild cousins to create a hybrid population of 129 birds with varying levels of courage. The creatures were subjected to the “open field test, which gauges animals’ valour by how they cope when placed in unfamiliar, brightly lit enclosures.
Some froze with fear or darted around in terror while others poked around curiously.
Scientists crunched their genomes to pinpoint the genetic regions that contributed to this variation in behaviour.
Further analysis highlighted 10 specific genes, six of which were already known to play a role in stress, anxiety and other brain functions. But three had no known association with behaviour, while the last gene had never been identified.
Three of the genes are also known to play a role in schizophrenia and bipolar disorder.
“We can’t yet prove these genes have equivalent functions in chicken and humans,” Dr Wright said. “(But) it raises the possibility that genes controlling variation in behaviour can be conserved between a whole variety of species.”
“Understanding the genetics underlying the chicken results may provide fundamental insights into normal behavioural variation in humans.”
He told The Australian the findings could lead to genetic screening tests for anxiety, and ultimately to new therapies.
This article first appeared on ‘The Australian’ on 6 December 2015.