Genome-wide association and genome partitioning reveal novel genomic regions underlying variation in gastrointestinal nematode burden in a wild bird

Identifying the genetic architecture underlying complex phenotypes is a notoriously difficult problem that often impedes progress in understanding adaptive eco-evolutionary processes in natural populations. Host–parasite interactions are fundamentally important drivers of evolutionary processes, but a lack of understanding of the genes involved in the host's response to chronic parasite insult makes it particularly difficult to understand the mechanisms of host life history trade-offs and the adaptive dynamics involved. Here, we examine the genetic basis of gastrointestinal nematode (Trichostrongylus tenuis) burden in 695 red grouse (Lagopus lagopus scotica) individuals genotyped at 384 genome-wide SNPs. We first use genome-wide association to identify individual SNPs associated with nematode burden. We then partition genome-wide heritability to identify chromosomes with greater heritability than expected from gene content, due to harbouring a multitude of additive SNPs with individuall...

解析复杂表型背后的遗传结构（genetic architecture）是一项公认的棘手难题，往往会阻碍我们理解自然种群中的适应性生态进化进程。宿主-寄生虫相互作用（Host–parasite interactions）是进化进程的核心重要驱动因子，但由于对宿主应对慢性寄生虫侵害所涉及的基因缺乏认知，我们尤其难以阐明宿主生活史权衡（host life history trade-offs）背后的机制以及相关的适应性动态（adaptive dynamics）。本研究针对695份经384个全基因组单核苷酸多态性（Single Nucleotide Polymorphism, SNP）位点完成基因分型的红松鸡（Lagopus lagopus scotica，苏格兰柳雷鸟）个体，开展了胃肠道线虫（Trichostrongylus tenuis）负荷的遗传基础研究。我们首先通过全基因组关联分析，筛选出与线虫负荷相关的单个SNP位点；随后对全基因组遗传力进行分区解析，以鉴定出那些因携带大量具有单个效应的加性SNP位点，进而遗传力高于基于基因含量预期值的染色体。