Genome-wide SNP and haplotype analyses reveal a rich history underlying dog domestication

Abstract

The development of the domestic dog is a fascinating example of a dramatic radiation in form and function that has occurred rapidly in association with the expansion of human civilization. An extensive genome-wide survey of over 48,000 single nucleotide polymorphisms in dogs and their wild progenitor, the grey wolf, reveals striking patterns of genetic subdivision. Two clearly divergent clusters emerge, one of ancient breeds and the other of modern breeds created in the nineteenth century. An analysis of haplotype sharing suggests that the dog has a dominant Middle Eastern or European origin, consistent with recent archaeological finds, rather than one in East Asia as suggested previously by mitochondrial DNA data. An extensive genome-wide survey of over 48,000 single nucleotide polymorphisms in dogs and their wild progenitor, the grey wolf, was conducted to shed light on the process of dog diversification. The results reveal that much of genome diversity came from Middle Eastern progenitors, combined with interbreeding with local wolf populations, and that recent evolution involved limited genetic variation to create the phenotypic diversity of modern dogs. Advances in genome technology have facilitated a new understanding of the historical and genetic processes crucial to rapid phenotypic evolution under domestication1,2. To understand the process of dog diversification better, we conducted an extensive genome-wide survey of more than 48,000 single nucleotide polymorphisms in dogs and their wild progenitor, the grey wolf. Here we show that dog breeds share a higher proportion of multi-locus haplotypes unique to grey wolves from the Middle East, indicating that they are a dominant source of genetic diversity for dogs rather than wolves from east Asia, as suggested by mitochondrial DNA sequence data3. Furthermore, we find a surprising correspondence between genetic and phenotypic/functional breed groupings but there are exceptions that suggest phenotypic diversification depended in part on the repeated crossing of individuals with novel phenotypes. Our results show that Middle Eastern wolves were a critical source of genome diversity, although interbreeding with local wolf populations clearly occurred elsewhere in the early history of specific lineages. More recently, the evolution of modern dog breeds seems to have been an iterative process that drew on a limited genetic toolkit to create remarkable phenotypic diversity.