Genomes of Friendly Foxes

A 2018 study is beginning to unpack some of the genetic mysteries of the now famous Russian farm fox experiment, where for more than 50 years foxes have been selectively bred for either puppy-like cuddly friendliness toward people all the way to extreme fear and hostility toward our kind. Much has been learned or at least inferred from this experiment about questions like how a long-ago wolf species could have evolved into your best friend who may at this moment be sleeping at your feet or chewing your slippers. Genetic technology has now caught up to the fox breeding selection experiment enough to allow us to begin to see what may have been happening genetically during domestication. A domesticated animal, which is what all dogs are, differs from its wild ancestors in having genetically-determined traits that powerfully facilitate its ability to form a relationship with our species. The new study, among whose authors is one of our National Canine Research Council advisors, Dr. Jessica Hekman, mapped the genomes of 30 red foxes, 10 from the “tame” group (the cheerful cuddly ones) 10 from the “aggressive” group (who try to escape from or scare people off) and 10 from the “conventional farm bred” group (who have not been bred for any particular behaviors and are presumably most like the original fox ancestors of the tame and aggressive foxes). First, the “tame” foxes are quite different genetically from the “aggressive” or “conventional” ones, who are a bit more like each other. The total findings offer nothing less than a possible window into what sets the scene for the kind of tolerance that makes harmonious social behavior across species lines possible. The researchers identified 103 genomic regions that highlight differences between the tame and aggressive foxes and found a particular gene that contributes to the tame behavior. In addition, these fox tameness regions overlap significantly with those that have been previously identified as main suspects in dog domestication, making the theoretical link between all dogs and foxes from the “tame” line even stronger, further shedding light on the question of how dogs became dogs.

Read the study in full: