COII TRANSFER RNA(LYS) INTERGENIC 9-BP DELETION AND OTHER MTDNA MARKERS CLEARLY REVEAL THAT THE THARUS (SOUTHERN NEPAL) HAVE ORIENTAL AFFINITIES

We searched for the East Asian mtDNA 9-bp deletion in the intergenic C OII/tRNA(Lys) region in a sample of 107 Tharus (50 from central Terai and 57 from eastern Terai), a population whose anthropological origin has yet to be completely clarified. The deletion, detected by electrop horesis of the PCR-amplified nt 7392-8628 mtDNA fragment after digesti on with HaeIII, was found in about 8% of both Tharu groups but was fou nd in none of the 76 Hindus who were examined as a non-Oriental neighb oring control population. A complete triplication of the 9-bp unit, th e second case so far reported, was also observed in one eastern Tharu. All the mtDNAs with the deletion, and that with the triplication, wer e further characterized (by PCR amplification of the relevant mtDNA fr agments and their digestion with the appropriate enzymes) to locate th em in the Ballinger et al. phylogeny of East Asian mtDNA haplotypes. T he deletion was found to be associated with four different haplotypes, two of which are reported for the first time. One of the deletions an d especially the triplication could be best explained by the assumptio n of novel length-change events. Ballinger's classification of East As ian mtDNA haplotypes is mainly based on the phenotypes for the DdeI si te at nt 10394 and the AluI site at nt 10397. Analysis of the entire T haru sample revealed that more than 70% of the Tharus have both sites, the association of which has been suggested as an ancient East Asian peculiarity. These results conclusively indicate that the Tharus have a predominantly maternal Oriental ancestry. Moreover, they show at lea st one and perhaps two further distinct length mutations, and this sug gests that the examined region is a hot spot of rearrangements.