The world’s oldest, and perhaps only, colony of friendly foxes may have revealed the gene driving tameness – a discovery with potential implications for research into human neurological disorders.
Keeping red foxes (Vulpes vulpes) in captivity on a large scale began in Canada in the late nineteenth century as farmers realised there was money to be made in the animals’ pelts. However, the foxes themselves weren’t domesticated, and always reacted to their human captors with fear or aggression (perhaps with good reason).
In 1959, however, researchers motivated more by curiosity than cash started a unique fox farm at the Institute of Cytology and Genetics of the Russian Academy of Sciences in St Petersburg. The scientists were interested in the mechanics of domestication and consistently selected foxes that showed affection for humans, cross-breeding them over more than 50 generations.
The result is a still-thriving, and still pure, population of extremely friendly animals.
In the 1960s, researchers at the institute set out to see if they could create the opposite – a population of foxes that reacted with unwavering aggression towards humans. They succeeded, again using conventional cross-breeding methods, and that population has now been around for more than 40 generations.
And as befits decent science, of course, the institute also hosts a third, control fox population that has not been bred to highlight any particular behavioural trait.
Given the integrity of the three populations, a team of researchers led by Anna Kukekova from the University of Illinois at Urbana-Champaign in the US reasoned that differences in the genomes of the three populations should indicate genes that are in some way involved in the expression of tameness or aggression.
Sequencing genomes from members of the nice, nasty and control populations, the scientists found 103 regions that differed between the three groups – and were therefore the result of selection pressures. Some of these included genes that are associated with neurological disorders in humans, including autism and bipolar, while others are known to code for tame behaviours in dogs.
However, they also identified what they termed “a strong positional candidate gene for tame behaviour”. This was a gene called SorCS1, which is involved in coding for proteins that regulate communication between neurons. In humans it is also associated with narcolepsy.
The St Petersburg fox colonies were established more than half a century ago, and given the turbulent history of Russia it perhaps seems remarkable that they have survived and been cared for in the interim.
The current study – published in the journal Nature Ecology & Evolution – was funded by research organisations in the US, Russia, China and Germany. With that amount of interest worldwide, it seems that the survival of the animals is pretty much guaranteed for the next half century.
“Decades of documented selection that have resulted in dramatic differences in the behaviour of tame and aggressive foxes render these populations valuable to genomic studies of behaviour,” the researchers conclude.