title: The Père David's deer MHC class I genes show unexpected diversity patterns, with monomorphic classical genes but polymorphic nonclassical genes and pseudogenes.
abstract: Père David's deer (Elaphurus davidianus) is a highly inbred species that arose from 11 founders but now comprises a population of about 3,000 individuals, making it interesting to investigate the adaptive variation of this species from the major histocompatibility complex (MHC) perspective. In this study, we isolated Elda-MHC class I loci using magnetic bead-based cDNA hybridization, and examined the molecular variations of these loci using single-strand conformation polymorphism (SSCP) and sequence analysis. We obtained seven MHC class I genes, which we designated F1, F12, G2, I7, AF, I8, and C1. Our analyses of stop codons, phylogenetic trees, amino acid conservation, and G+C content revealed that F1, F12, G2, and I7 were classical genes, AF was a nonclassical gene, and I8 and C1 were pseudogenes. Our subsequent molecular examinations showed that the diversity pattern in the Père David's deer was unusual. Most mammals have more polymorphic classical class I loci vs. the nonclassical and neutral genes. In contrast, the Père David's deer was found to be monomorphic at classical genes F1, F12, G2, and I7, dimorphic at the nonclassical AF gene, dimorphic at pseudogene I8, and tetramorphic at pseudogene C1. The adverse polymorphism patterns of Elda-I genes might provide evidence for selection too faster deplete MHC variation than drift in the bottlenecked populations, while the postbottleneck tetramorphism of the C1 pseudogene appears to be evidence of strong historical balancing selection.
authors: The Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Sciences, Zhejiang University, Hangzhou, PR China.
authors: Pei
authors: P
authors: Zhang
authors: Ye-Ye
authors: YY
authors: Kuang
authors: Hai-Long
authors: HL
authors: Wu
authors: Ling
authors: L
authors: Li
authors: Yun-Fa
authors: YF
authors: Ge
authors: Qiu-Hong
authors: QH
authors: Wan
authors: Sheng-Guo
authors: SG
authors: Fang
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics*; D000818:Animals; D001482:Base Composition; D001483:Base Sequence; D002681:China; D003670:Deer / Q000235:genetics*; D005805:Genes, MHC Class I / Q000235:genetics*; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic / Q000235:genetics*; D018807:Polymorphism, Single-Stranded Conformational; D011544:Pseudogenes / Q000235:genetics*; D017422:Sequence Analysis, DNA