In this study the previously proposed hypothesis that extant North American wolves originate from multiple waves of colonization from Asia is tested, along with the hypothesis that land connections have been important in the evolutionary history of other isolated wolf populations in Japan.

Morphological and physiological diversity observed in domestic species is strikingly greater than that seen in wild species. To explain this diversity, a hypothesis was proposed some decades ago that suggested that selective forces imposed on domestic species (plants and animals) would have led to higher recombination rate in the genome of domesticates, thus allowing for new combinations of alleles, and thus also of characters. However, this hypothesis had never been conclusively tested....