Gaur L K, Hughes A L, Heise E R, Gutknecht J
Department of Microbiology and Immunology, Bowman Gray School of Medicine.
Mol Biol Evol. 1992 Jul;9(4):599-609. doi: 10.1093/oxfordjournals.molbev.a040748.
To understand the evolution of the class II major histocompatibility complex (MHC) DQB1 locus in primates, the second exons of seven DQB1 alleles from five non-human primate species were amplified by polymerase chain reaction. Comparisons of these and other primate sequences show that no between-species diversity is greater than within-species diversity, suggesting maintenance of DQB1 alleles through the history of Old-World primates. There is a preponderance of nonsynonymous nucleotide substitutions at antigen-binding-site codons; this pattern is in marked contrast to what is seen at the closely related, presumably nonfunctional DQB2 gene. The results support the hypothesis that DQB1 polymorphism is maintained by overdominant selection relating to antigen presentation.
为了解灵长类动物中II类主要组织相容性复合体（MHC）DQB1基因座的进化情况，通过聚合酶链反应扩增了来自5种非人类灵长类物种的7个DQB1等位基因的第二个外显子。对这些序列以及其他灵长类序列的比较表明，种间多样性不大于种内多样性，这表明在旧世界灵长类动物的历史中DQB1等位基因得以维持。在抗原结合位点密码子处存在大量非同义核苷酸替换；这种模式与在密切相关的、可能无功能的DQB2基因中所见的情况形成鲜明对比。这些结果支持了以下假设，即DQB1多态性是通过与抗原呈递相关的超显性选择得以维持的。
