Anthro-genetics on Paleomongoloid in Pan-Pacific and Northland Areas

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Human T-cell leukemia virus type 1 (HTLV-l) is spreading throughout the world with microgeographical clusters of hyperendemicity. Epidemiologic evidences on HTLV among Mongoloids in the world showed that HTLV-l is highly endemic in South Japan and in the Andes district of South America. In the other hand HTLV type 2 (HTLV-II) is broadly distributed in the whole South America except the Andes line. The HLA haplotypes of these two carriers were mutually exclusive, i.e., the HLA haplotypes of Andes HTLV-I carriers were common among Japanese while those of HTLV-II carriers were prevalent among North American Indians. This suggested that HLA haplotypes might be ethnically segregated among South American natives and might be involved in the genetic susceptibility to HTLV-I and HTLV-II infections. In a previous study in this program, gene fractions of proviral HTLV-I from Andean mummy aged 1500 years was detected. This observation suggested that HTLV-I may have existed at least 1000 years before aboriginal Andean migrated from the Asian Continent and settled down in the Andes.In Tibetan populations in China, the hepatitis B virus (HBV) genotypes have not yet been studied up until now. HBV distributed in the world is classified into seven genotypes, designated as A to G, geographically separated. Since the prevalence of HBV infection in isolated Tibetan people in the east and west regions of Tibet was very high, the HBV genotypes were determined by PCR-microwell plate hybridization method using plasma DNA. We detected only genotype in Tibetan HBV This genotype C is known to be a predominant type of HBV among Asian Mongoloids, especially in Thailand and Korea These results revealed that the Tibetan villagers are not exposed by HTLV-I but highly infected with HBV, especially with genotype C. HBV and HLA gene sequences warrant further investigation in this context.