Genes that may be associated with tame and aggressive behaviour in red foxes are revealed in a study published online this week in Nature Ecology & Evolution. Studying the red fox may help illuminate the genetic basis of social behaviour, including human behavioural disorders.

Red foxes have been bred successfully in captivity for over a century, and have adapted to the farm environment. Unlike their dog cousins, however, captive foxes generally exhibit fear or aggression toward humans. Beginning in the 1960s, a programme to experiment with domesticating farm-bred foxes established a tame strain of foxes, selected to be eager for human interaction, and an aggressive strain selected for behaving violently toward humans. A third population of foxes were not selected for any particular behaviour. These experimental populations provide a unique opportunity to determine the genetic basis of tame and aggressive behaviour.

Anna Kukekova, Guojie Zhang and colleagues sequence a reference red fox genome and analyse re-sequenced genomes of foxes from the tame, aggressive and conventionally farm-bred populations. They identify 103 genomic regions targeted by selection in the three fox strains, including several genes that in humans are associated with neurological disorders including autism spectrum disorder and bipolar disorder.

The authors find that a strong candidate for tame behaviour is the gene SorCS1, which regulates proteins involved in the communication between neurons. The authors conclude that the red fox provides a robust model for understanding the genetic basis of social behaviour, which is a long-standing question in evolutionary biology and human genetics.