Martin Alynn M, Cassirer E Frances, Waits Lisette P, Plowright Raina K, Cross Paul C, Andrews Kimberly R
United States Geological Survey Northern Rocky Mountain Science Center Bozeman MT USA.
Idaho Department of Fish and Game Lewiston ID USA.
Ecol Evol. 2021 Mar 2;11(6):2488-2502. doi: 10.1002/ece3.7159. eCollection 2021 Mar.
Genetic composition can influence host susceptibility to, and transmission of, pathogens, with potential population-level consequences. In bighorn sheep (), pneumonia epidemics caused by have been associated with severe population declines and limited recovery across North America. Adult survivors either clear the infection or act as carriers that continually shed and expose their susceptible offspring, resulting in high rates of lamb mortality for years following the outbreak event. Here, we investigated the influence of genomic composition on persistent carriage of in a well-studied bighorn sheep herd in the Wallowa Mountains of Oregon, USA. Using 10,605 SNPs generated using RADseq technology for 25 female bighorn sheep, we assessed genomic diversity metrics and employed family-based genome-wide association methodologies to understand variant association and genetic architecture underlying chronic carriage. We observed no differences among genome-wide diversity metrics (heterozygosity and allelic richness) between groups. However, we identified two variant loci of interest and seven associated candidate genes, which may influence carriage status. Further, we found that the SNP panel explained ~55% of the phenotypic variance (SNP-based heritability) for carriage, though there was considerable uncertainty in these estimates. While small sample sizes limit conclusions drawn here, our study represents one of the first to assess the genomic factors influencing chronic carriage of a pathogen in a wild population and lays a foundation for understanding genomic influence on pathogen persistence in bighorn sheep and other wildlife populations. Future research should incorporate additional individuals as well as distinct herds to further explore the genomic basis of chronic carriage.
基因组成可影响宿主对病原体的易感性及病原体的传播，可能会对种群水平产生影响。在大角羊中，由[病原体名称未给出]引起的肺炎疫情与北美地区严重的种群数量下降及恢复受限有关。成年幸存者要么清除感染，要么成为持续排出[病原体名称未给出]并感染其易感后代的携带者，导致疫情爆发后的数年里羔羊死亡率居高不下。在此，我们在美国俄勒冈州瓦洛厄山脉一个经过充分研究的大角羊群中，调查了基因组组成对[病原体名称未给出]持续携带的影响。我们利用RADseq技术为25只雌性大角羊生成了10,605个单核苷酸多态性（SNP），评估了基因组多样性指标，并采用基于家系的全基因组关联方法来了解慢性携带背后的变异关联和遗传结构。我们观察到两组之间在全基因组多样性指标（杂合性和等位基因丰富度）上没有差异。然而，我们确定了两个感兴趣的变异位点和七个相关候选基因，它们可能影响携带状态。此外，我们发现SNP面板解释了[病原体名称未给出]携带的约55%的表型方差（基于SNP的遗传力），不过这些估计存在相当大的不确定性。虽然样本量小限制了在此得出的结论，但我们的研究是首批评估影响野生种群中病原体慢性携带的基因组因素的研究之一，为理解基因组对大角羊及其他野生动物种群中病原体持久性的影响奠定了基础。未来的研究应纳入更多个体以及不同的羊群，以进一步探索慢性携带的基因组基础。
