Nucleotide sequence polymorphism of the HLA-A gene in Asia-Pacific populations.
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文摘
Using the PCR-SSO typing technique recently developed in our laboratory the nucleotide sequence polymorphism of the HLA-A gene was investigated in 15 populations from Australia, Indonesia, Melanesia, Micronesia, Polynesia and China. A total number of 22 HLA-A alleles were detected including four novel alleles found in the present study. White Australians and northern Chinese showed the highest HLA-A polymorphism with 20 and 16 alleles detected respectively. On the contrary, very limited heterogeneity was observed in Aboriginal Australians and Pacific populations. In native Australian groups only four alleles, A*0201, A*1101, A*2402 and A*3401 were identified as aboriginal. Interestingly, each of the four aboriginal alleles represents one of the five major HLA-A allele families with extensive structural and functional differences between them. Several lines of evidence indicated that the rather simple HLA-A profile in Aborigines is the result of overdominant selection combined with other evolutionary forces such as the founder effect, population bottlenecks and the long history of isolation of these people. Among major HLA-A allele groups A2 was found the most diversified with five subtypes detected in the study populations including A*0201, 0203, 0205, 0206 and 0207. In northern Chinese A*02 subtypes other than A*0201 accounted for half of the A2 gene frequency while in Polynesian populations HLA-A2 was overwhelmingly dominated by the oriental subtype A*0206. The present study demonstrated that comprehensive DNA typing for HLA-A may help to improve the outcome of unrelated bone marrow transplantation. Estimated on the gene frequencies in the population, 40 % of northern Chinese and 20 % of white Australian donor-recipient pairs thought to be matched for HLA-A by serology would be mismatched.