Taming of the bunny rewrote rabbit genome

Pet rabbits will happily sit in their owner's lap, but wild rabbits are famously timid, fleeing at the slightest hint of a human, let alone a fox or hawk. 

This tolerance for human company was only bred into bunnies recently: about 1400 years ago in southern France. But it was not clear how this worked at the genetic level. Did domestication make drastic changes to a few important genes, or many subtle alterations?

To find out, Leif Andersson at Uppsala University in Sweden and his colleagues compared the genomes of pet rabbits with those of their wild counterparts (Oryctolagus cuniculus) from Spain and southern France.

No genes had been turned off outright, a process that in theory might have helped reduce fear of humans. "Gene loss has not played a prominent role during rabbit domestication," says Andersson.

Instead, the team found that lots of small, pre-existing genetic variations became more common in rabbits as they were domesticated. Most of these variations involved just one letter of DNA code. All in all, about 100 regions were selected to be different in the domesticated rabbits.

Rather than affecting the genes themselves, most of the DNA tweaks were in regulatory regions of the genome, which control whether genes are switched on or off. "Wild and domestic rabbits do not differ so much in actual protein sequences, but in how gene and protein expression is regulated," says Andersson.