Gyllensten U, Bergström T, Josefsson A, Sundvall M, Savage A, Blumer E S, Giraldo L H, Soto L H, Watkins D I
Department of Medical Genetics, Beijer Laboratory, University of Uppsala, Sweden.
Immunogenetics. 1994;40(3):167-76. doi: 10.1007/BF00167076.
Cotton-top tamarins (Saguinus oedipus) in captivity are unusual in that they exhibit low levels of polymorphism and allelic diversity at the major histocompatibility complex (Mhc) class I loci. Since the polymorphism has previously only been examined in captive tamarins, we analyzed the Mhc class I alleles of a population of wild tamarins. These wild tamarins, like their captive counterparts, exhibited limited class I polymorphism. We also assessed the levels of polymorphism and allelic diversity at the Mhc class II DQA1, DQB1, DQB2, and the DRB loci in captive populations of cotton-top tamarins. In contrast to the extensive polymorphism in Old World monkeys, only two alleles were detected at each of DQA1 and DQB1. Also, the DQB2 locus was monomorphic and conserved between New and Old World monkeys. Sequences derived from four putative DRB loci were obtained, and extensive polymorphism was found at all four loci. Phylogenetic analysis did not indicate that any of the tamarin DRB loci, with the possible exception of Saoe-DRB3, were orthologous to the human DRB loci. At three of the DRB loci (Saoe-DRB11, Saoe-DRBW12, Saoe-DRBW22), the number of nonsynonymous changes was higher than the number of synonymous changes in the putative antigen recognition sites, indicative of positive selection. We found no support for a restriction on the polymorphism at the cotton-top tamarin class II loci. However, the allelic diversity at some of the Saoe-DRB loci is more limited than for the HLA-DRB1, consistent with a restriction imposed by the bone marrow-chimerical lifestyle.
圈养的棉顶狨猴（Saguinus oedipus）具有独特之处，即它们在主要组织相容性复合体（Mhc）I类基因座上表现出低水平的多态性和等位基因多样性。由于此前仅在圈养狨猴中研究过这种多态性，我们分析了一群野生狨猴的Mhc I类等位基因。这些野生狨猴与其圈养同类一样，I类多态性有限。我们还评估了圈养棉顶狨猴群体中Mhc II类DQA1、DQB1、DQB2和DRB基因座的多态性水平和等位基因多样性。与旧世界猴的广泛多态性形成对比的是，在DQA1和DQB1中每个仅检测到两个等位基因。此外，DQB2基因座是单态的，并且在新旧世界猴之间保守。获得了来自四个假定DRB基因座的序列，并且在所有四个基因座上都发现了广泛的多态性。系统发育分析并未表明任何狨猴DRB基因座（可能除了Saoe - DRB3）与人类DRB基因座是直系同源的。在三个DRB基因座（Saoe - DRB11、Saoe - DRBW12、Saoe - DRBW22）中，假定抗原识别位点的非同义变化数量高于同义变化数量，表明存在正选择。我们没有发现支持棉顶狨猴II类基因座多态性受到限制的证据。然而，一些Saoe - DRB基因座的等位基因多样性比HLA - DRB1更有限，这与骨髓嵌合生活方式所施加的限制一致。
