An international team of scientists has successfully sequenced the genome of the red fox (Vulpes vulpes).
The red fox (Vulpes vulpes). Image credit: Dia Picard.
The domestic dog and the red fox are closely related species that only diverged about 10 million years ago within the family Canidae. However, these two species occupy very different ecological niches.
The red fox has a geographic range wider than that of any other wild species in the order Carnivora and has even become a common resident of many major cities.
The dog, on the other hand, has become widespread for a different reason: it was domesticated from the gray wolf at least 15,000 years ago and became man’s best friend.
“We’ve been waiting for this tool for a very, very long time,” said lead author Dr. Anna Kukekova, a researcher at the University of Illinois.
“In our previous work, we tried to identify regions of the fox genome responsible for tame and aggressive behavior, but these studies required a reference genome and all we could use was the dog genome. For us, the fox genome provides a much better resource for genetic analysis of behavior.”
After sequencing and assembling the fox genome, Dr. Kukekova and colleagues sequenced a group of foxes from the tame, aggressive and conventional farm-bred populations to identify genomic regions associated with the response to selection for behavior.
They decoded the genomes of 10 individuals from each population, then compared them to the full fox genome and each other.
The three populations differed in 103 genomic regions, some of which turn out to be responsible for the tame and aggressive behaviors.
“Finding genomic regions at such resolution was beyond any expectations with our previous tools,” Dr. Kukekova said.
“Now, for the first time, we could not only pinpoint part of a chromosome which makes foxes more tame or aggressive, but we could identify specific genes responsible for it.”
The researchers compared the 103 genomic regions to those of other sequenced mammals and found some compelling similarities.
For example, they identified matches between behavior regions in foxes with regions important in domestication in dogs and with a region associated with Williams-Beuren syndrome in humans, a genetic disorder characterized by extremely outgoing, friendly behavior.
“Oddly enough, we found the Williams-Beuren region in aggressive foxes, not tame ones. We thought it would be the opposite,” Dr. Kukekova said.
“The mysterious finding underscores how much more research is needed before the regions are fully understood.”
The results were published online August 6 in the journal Nature Ecology & Evolution.
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Anna V. Kukekova et al. Red fox genome assembly identifies genomic regions associated with tame and aggressive behaviours. Nature Ecology & Evolution, published online August 6, 2018; doi: 10.1038/s41559-018-0611-6
