[HLA-DRB1 gene polymorphism of Naxi ethnic group of Yunnan Province, China and its ethnological evolution analysis]

The HLA-DRB1 gene polymorphism of Naxi ethnic group of Yunnan Province, China was investigated for the first time using high resolution PCR-SBT method, which is based on sequences of HLA-DRB1 Intron 1 and Intron 2 with our improvement. From 60 individuals of Naxi 37 DRB1 alleles were detected. The distribution of allele frequencies is evenly spread for most of alleles detected in Naxi. However, the gene frequency for HLA-DRB1 * 12021 is 17.50%. The other common alleles (> 5%) were HLA-DRB1 * 1404(7.50%), 1504(5.83%), 04051(5.83%), 08032(5.83%), 09012(5%), 03011(5%), and they covered 35% of the total alleles detected from Naxi, and 52.49% after adding the frequency of HLA-DRB1 * 12021. HLA-DRB1 * 0305, 0438, 1123, 1132, 1310, 0812 were detected in Chinese for the first time, and were very rare in other ethnic groups worldwide. Using the HLA-DRB1 gene frequencies of various ethnic groups, we constructed the phylogenetic tree by Fitch-Margoliash and Least-Squares Distance Methods and Cavalli-Sforza's chord measure of genetic distance. In our dendrogram, the South China populations were clustered together, and Siberian, Japanese and Minority of North China were clustered together, in which two big clusters we thought represented the ancient Southern and Northern Mongolian. Our results showed Naxi was clustered with Lahu and Yao ethnic groups, which were in the cluster of South China population. Obviously Naxi belongs to the South China ethnic groups and can't trace its origin from northern ethnic groups with the HLA-DRB1 genetic data. But based on Naxi's historical folklore, it was down to Southern China from Northwest China. The preliminary analysis about its origin conundrum was discussed in this paper based on our genetic data in relationship with its history and ethnology studies.