Erik Axelsson of Uppsala University in Sweden and his colleagues analyzed DNA from 12 wolves and 60 dogs representing 14 diverse breeds, looking for regions of the dog genome that evolved under selection pressure during domestication. Their search identified a number of probable targets of selection, including some genes related to central nervous system development. This is not unexpected. Modern dogs are well known to differ from wolves in having reduced aggression and social-cognitive skills that allow them to communicate with humans in special ways. Mutations in some of the nervous system genes highlighted by this study may have produced some of those behavioral changes that made Fido our BFF.
Intriguingly, genes involved in the metabolism of starch showed up among the targets, too. In fact, the study revealed that during the domestication of dogs, selection acted on genes involved in all three of the stages of starch digestion, promoting mutations that facilitated adaptation from a meat-centric diet to one heavy on starch. “Our results show that adaptations that allowed the early ancestors of modern dogs to thrive on a diet rich in starch, relative to the carnivorous diet of wolves, constituted a crucial step in early dog domestication,” the authors write in a paper published in the January 24 Nature. “This may suggest that a change of ecological niche could have been the driving force behind the domestication process, and that scavenging in waste dumps near the increasingly common human settlements during the dawn of the agricultural revolution may have constituted this new niche.”
Cats may have followed the same route, but we don't like to talk about them around here.