Allelic distribution of HLA class I genes in the Tibetan ethnic population of China
Allelic distribution of HLA class I genes in the Tibetan ethnic population of China
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DOI：
10.1111/j.1744-313x.2006.00637.x
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发表时间：
2006-12-01
影响因子：
2.2
通讯作者：
Xu, A.
中科院分区：
文献类型：
--
作者：
Chen, S.;Hong, W.;Xu, A.
藏族生活在海拔约4000米的青藏高原上。在中国西南部。考古证据表明，至少在5000年前，西藏就有人类居住。然而，西藏的早期历史仍然难以捉摸。本研究采用基于测序的分型方法对 158 名无关藏族人中人类白细胞抗原 (HLA)-A、-B 和 -Cw 等位基因分布进行了调查，共鉴定出 25 个 HLA-A、45 个 HLA-B 和 20 个 HLA-Cw 等位基因。 A*24G1 (27.2%)、B*51G1 (16.8%)、Cw*04G1 (13.3%) 和 Cw*070201G1 (13.3%) 是最常见的 HLA-A、-B 和 -Cw 等位基因。最常检测到的单倍型是 A*24G1-B*51G1-Cw*140201 (3.6%)、A*24G1-B*51G1 (6.8%)、A*02G1-Cw*070201G1 (6.5%) 和 B*51G1-Cw*140201 (5.0%)。卡方检验表明所有三个基因座均符合 Hardy-Weinberg 预期。没有观察到 HLA-A 和 -B 基因座偏离选择性中性的证据。然而，HLA-Cw 观察到的纯合性与预期值存在显着偏差。虽然当代藏族居住在中国西南部，但内伊基于HLA-A、-B和-Cw频率的遗传距离测量表明，藏族更接近北方汉族、蒙古族、朝鲜族和日本人，而不是南方汉族。根据邻接法构建的相应树状图支持藏族从南方汉族中分离出来，位于包括北方汉族和蒙古族的东北亚族群中。这些数据与语言分类以及最近的假设非常一致，即藏语可能起源于中国北部黄河沿岸。
Tibetans live in Qinghai-Tibet Plateau rising about 4000 m a.s.l. in south-west China. Archaeological evidences suggested that there have been humans living in Tibet at least 5000 years ago. However, Tibetan earlier history remains elusive. In the present study, allelic distribution of human leucocyte antigen (HLA)-A, -B and -Cw in 158 unrelated Tibetan Chinese was investigated using sequencing-based typing methods, and a total of 25 HLA-A, 45 HLA-B and 20 HLA-Cw alleles were identified. A*24G1 (27.2%), B*51G1 (16.8%), Cw*04G1 (13.3%) and Cw*070201G1 (13.3%) are the most common HLA-A, -B and -Cw alleles. The most frequently detected haplotypes were A*24G1-B*51G1-Cw*140201 (3.6%), A*24G1-B*51G1 (6.8%), A*02G1-Cw*070201G1 (6.5%) and B*51G1-Cw*140201 (5.0%). Chi-squared test suggested that all three loci fitted the Hardy-Weinberg expectations. No evidence for a departure from selective neutrality at the HLA-A and -B loci was observed. However, significant departure of the observed homozygosity from the expected values was found for HLA-Cw. Though the contemporary Tibetans inhabit the south-west China, Nei's genetic distance measure based on frequencies of HLA-A, -B and -Cw indicated that Tibetans were closer to northern Han Chinese, Mongolian Chinese, Koreans and Japanese rather than to southern Han Chinese. The corresponding dendrogram constructed according to the neighbour-joining method supported that Tibetans separated from southern Han and located in North-East Asian cluster which included northern Han Chinese and Mongolian Chinese. These data were in good agreement with language classification and with a recent hypothesis that Tibetan might originate from northern China along Yellow river.