Mitochondrial DNA polymorphisms in Yunnan nationalities in China

Nucleotide sequences of the D-loop region of human mitochondrial DNA from f our Yunnan nationalities, Dal, Wa, Lahu, and Tibetan, were analyzed. Based on a comparison of 563-bp sequences in 99 people, 66 different sequence typ es were observed. Of these, 64 were unique to their respective populations, whereas only 2 types were shared between the Lahu and Wa nationalities. Th e D-loop sequence variation and phylogenetic analysis suggested that the 99 mtDNA lineages were classified into eight clusters in the phylogenetic tre e. All lineages that had a 9-bp deletion in the COII/tRNA(Lys) intergenic r egion appeared in one cluster in the D-loop tree, suggesting a single event of the deletion in the Yunnan nationalities studied. Genetic distances, ba sed on net nucleotide diversities between populations including Han Chinese and mainland Japanese, revealed that the Dal, Wa, Lahu, and Han Chinese ar e closely related to each other, while Tibetan and mainland Japanese formed a single cluster. The bootstrap probability of separation between the Dai- Wa-Lahu-Chinese clade and the Tibetan-Japanese clade was 99%, indicating th at there are at least two different origins among minority groups in Yunnan province. Although the genetic distance between Tibetan and Japanese withi n the clade is rather long, the results may shed light on the origins of ma inland Japanese.