西藏珞巴族HLA-DRB1基因多态性

目的：检测西藏珞巴族HLA-DRB1等位基因及基因型频率，并将其与18个人群的HLA-DRB1频率进行比较，绘制系统发生树。方法：应用聚合酶链反应-序列特异性寡核苷酸探针(PCR-SSO)技术，对我国西藏南部林芝地区3代内无血缘关系的92个珞巴族健康个体进行了HLA-DRB1位点的基因分型。采用不加权配对组算术方法（UPGMA）绘制系统发生树。结果：在92例珞巴族个体的184个等位基因中共检出11种HLA-DRB1等位基因，其中HLA-DRB1*04(27.20%)，DRB*12(25.50%)在珞巴族中最常见，共占珞巴族可检出等位基因的52.70％；其他频率大于5％的等位基因还有DRB1*14(15.20%)，DRB1*15(9.80%)和DRB1*08(8.20%)。结论：西藏珞巴族HLA-DRB1等位基因分布与其他华人群体均存在很大的差异，显示其HLA等位基因频率分布的民族独特性；在遗传距离上珞巴族和藏族最近，这与民族学、历史学和社会学研究结果相一致。

Determination of HLA-DRB1 gene polymorphism in Luoba ethnic group of Tibet

Objective To investigate the frequencies of allele and genotype of HLA-DRB1 gene in Luoba ethnic group. Methods HLA-DRB1 genes from 92 individuals of Luoba ethnic group in Tibet Autonomous region were investigated, using PCR-SSO (polymerase chain reaction -sequence specific oligo-nucleotide) genotyping methods. We compared allele frequencies of Luoba population in HLA-DRB1 locus with that of various ethnic groups distributed worldwide, constructed the phylogenetic tree by UPGMA (unweighted pair group method with arithmetic mean), and counted genetic distance by Nei measure. Results Of the 11 DRB1 alleles detected, the two most common genes were DRB1*04 (gene frequency: 27.20%) and DRB*12 (25.50%), which covered 52.70% of the total alleles detected from Luoba ethnic group. The frequencies of HLA-DRB1*14 (15.20%), DRB1*15 (9.80%) and DRB1*08 (8.20%) were more than 5%. Luoba was unique in the distribution of HLA alleles. The genetic distance between Luoba and Tibetan was closer than that with other population. A dendrogram based on the DRB1 genes by cluster analysis suggested that Luoba ethnic group might cluster with Tibetan firstly, then cluster with other population living in China (except Uygr), and cluster with Caucasian and Black finally. Conclusion The HLA-DRB1 gene frequency of Luoba individuals in Tibet Linzhi had some differences compared with that of other Chinese population. The kindred relation between Luoba and Tibetan was closer than that with other population, which was coincident with the results of ethnology, history and sociology.