Department of Natural History Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan.
Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan.
PLoS One. 2022 May 10;17(5):e0267609. doi: 10.1371/journal.pone.0267609. eCollection 2022.
The wolverine (Gulo gulo) in Finland has undergone significant population declines in the past. Since major histocompatibility complex (MHC) genes encode proteins involved in pathogen recognition, the diversity of these genes provides insights into the immunological fitness of regional populations. We sequenced 862 amplicons (242 bp) of MHC class II DRB exon 2 from 32 Finnish wolverines and identified 11 functional alleles and three pseudogenes. A molecular phylogenetic analysis indicated trans-species polymorphism, and PAML and MEME analyses indicated positive selection, suggesting that the Finnish wolverine DRB genes have evolved under balancing and positive selection. In contrast to DRB gene analyses in other species, allele frequencies in the Finnish wolverines clearly indicated the existence of two regional subpopulations, congruent with previous studies based on neutral genetic markers. In the Finnish wolverine, rapid population declines in the past have promoted genetic drift, resulting in a lower genetic diversity of DRB loci, including fewer alleles and positively selected sites, than other mustelid species analyzed previously. Our data suggest that the MHC region in the Finnish wolverine population was likely affected by a recent bottleneck.
在过去，芬兰的狼獾（Gulo gulo）经历了显著的种群数量下降。由于主要组织相容性复合体（MHC）基因编码参与病原体识别的蛋白质，这些基因的多样性为了解区域种群的免疫适应性提供了线索。我们从 32 只芬兰狼獾中测序了 MHC 类 II DRB 外显子 2 的 862 个扩增子（242bp），鉴定出 11 个功能等位基因和 3 个假基因。分子系统发育分析表明存在跨物种多态性，PAML 和 MEME 分析表明存在正选择，表明芬兰狼獾的 DRB 基因在平衡和正选择的作用下进化。与其他物种的 DRB 基因分析不同，芬兰狼獾的等位基因频率清楚地表明存在两个区域亚种群，与以前基于中性遗传标记的研究结果一致。在芬兰狼獾中，过去的快速种群下降促进了遗传漂变，导致 DRB 基因座的遗传多样性降低，包括较少的等位基因和正选择位点，低于以前分析的其他鼬科物种。我们的数据表明，芬兰狼獾种群的 MHC 区域可能受到了最近瓶颈效应的影响。
