An international collaboration involving INRA research scientists has evidenced the impact of domestication of the rabbit on its genetic heritage, thanks to sequencing of its genome. In particular, the scientists have shown that the genes controlling brain and neuronal development were specifically targeted by the domestication process. These results, published on 29 August 2014 in Science, help us to better understand and trace the evolution of genomes and how they adapt over time.
The domestication of animals is accompanied by modifications to their behaviour, physiology and morphology. But how does it change the genomes of different animals? Although the dog, and most farmed livestock such as the cow, goat, sheep or pig, were domesticated between 9000 and 15,000 years ago, the rabbit was only recently domesticated (some 1400 years ago). At that time, the wild ancestor of the domestic rabbit was confined to southern France and the Iberian peninsula. Since then, wild and domestic rabbits have lived in large numbers under similar climatic conditions. The rabbit thus represents a good model to study the genetic modifications associated with domestication.
INRA scientists working with colleagues from the Broad Institute (Boston, USA), Uppsala University (Sweden) and the University of Porto (Portugal) participated in the first instance in producing a reference sequence1 of the rabbit genome. This was then compared with the genomes of six domestic rabbit breeds (New Zealand, Bélier Français, Belgian Hare, Dutch, Géant des Flandres and Argenté de Champagne) and those of 14 wild rabbits caught in southern France and the Iberian peninsula. The scientists were not able to identify any major domestication gene, but observed a very large number of polymorphisms (genomic variations) spread throughout the genome that in particular concerned the gene regulatory regions. The research team also showed that these polymorphisms notably affected the genes involved in development of the brain and nervous system.
Unlike the domestic rabbit, its wild counterpart benefits from an ability to take rapid flight in the face of its numerous predators (birds of prey, foxes, humans). This study showed that it was an accumulation of genetic variations with minor effects affecting a very large number of genes during domestication that have gradually inhibited this aptitude, which thus represents one of the most important changes in the evolutionary history of the rabbit.
As a livestock animal bred notably for its meat and fur, as a pet or as a model animal for human medicine, the rabbit is a species with numerous interesting features. By focusing on the traces of selection observed at the scale of the whole genome, it has now been shown that this animal is a remarkable model to study domestication processes in mammals.