Hans Jörg B, Bergl Richard A, Vigilant Linda
Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany.
North Carolina Zoological Park, Asheboro, NC, 27205, USA.
Immunogenetics. 2017 May;69(5):303-323. doi: 10.1007/s00251-017-0974-x. Epub 2017 Mar 22.
Comparisons of MHC gene content and diversity among closely related species can provide insights into the evolutionary mechanisms shaping immune system variation. After chimpanzees and bonobos, gorillas are humans' closest living relatives; but in contrast, relatively little is known about the structure and variation of gorilla MHC class I genes (Gogo). Here, we combined long-range amplifications and long-read sequencing technology to analyze full-length MHC class I genes in 35 gorillas. We obtained 50 full-length genomic sequences corresponding to 15 Gogo-A alleles, 4 Gogo-Oko alleles, 21 Gogo-B alleles, and 10 Gogo-C alleles including 19 novel coding region sequences. We identified two previously undetected MHC class I genes related to Gogo-A and Gogo-B, respectively, thereby illustrating the potential of this approach for efficient and highly accurate MHC genotyping. Consistent with their phylogenetic position within the hominid family, individual gorilla MHC haplotypes share characteristics with humans and chimpanzees as well as orangutans suggesting a complex history of the MHC class I genes in humans and the great apes. However, the overall MHC class I diversity appears to be low further supporting the hypothesis that gorillas might have experienced a reduction of their MHC repertoire.
对密切相关物种之间的MHC基因含量和多样性进行比较，可以深入了解塑造免疫系统变异的进化机制。在黑猩猩和倭黑猩猩之后，大猩猩是人类现存的最近的亲属；但相比之下，我们对大猩猩MHC I类基因（Gogo）的结构和变异了解相对较少。在这里，我们结合了长距离扩增和长读长测序技术，对35只大猩猩的全长MHC I类基因进行了分析。我们获得了50条全长基因组序列，分别对应15个Gogo-A等位基因、4个Gogo-Oko等位基因、21个Gogo-B等位基因和10个Gogo-C等位基因，其中包括19个新的编码区序列。我们分别鉴定出两个以前未检测到的与Gogo-A和Gogo-B相关的MHC I类基因，从而说明了这种方法在高效和高精度MHC基因分型方面的潜力。与它们在人科中的系统发育位置一致，单个大猩猩MHC单倍型与人类、黑猩猩以及猩猩具有共同特征，这表明人类和大猩猩的MHC I类基因有着复杂的历史。然而，MHC I类基因的总体多样性似乎较低，这进一步支持了大猩猩的MHC库可能已经减少的假说。
