Mitochondrial DNA variation and evolution of Japanese black cattle (Bos taurus)

This article describes complete mitochondrial DNA displacement loop sequences from 32 Japanese Black cattle and the analysis of these data in conjunction with previously published sequences from African, European, and Indian subjects. The origins of North East Asian domesticated cattle are unclear. The earliest domestic cattle in the region were Bos taurus and may have been domesticated from local wild cattle (aurochsen; B. primigenius), or perhaps had an origin in migrants from the early domestic center of the Near East. In phylogenetic analyses, taurine sequences form a dense tree with a center consisting of intermingled European and Japanese sequences with one group of Japanese and another of all African sequences, each forming distinct clusters at extremes of the phylogeny. This topology and calibrated levels of sequence divergence suggest that the clusters may represent three different strains of ancestral aurochs, adopted at geographically and temporally separate stages of the domestication process. Unlike Africa, half of Japanese cattle sequences are topologically intermingled with the European variants. This suggests an interchange of variants that may be ancient, perhaps a legacy of the first introduction of domesticates to East Asia.