Miller Joshua M, Festa-Bianchet Marco, Coltman David W
Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
Current affiliation: Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA.
PeerJ. 2018 Feb 12;6:e4364. doi: 10.7717/peerj.4364. eCollection 2018.
Elucidating the genetic basis of fitness-related traits is a major goal of molecular ecology. Traits subject to sexual selection are particularly interesting, as non-random mate choice should deplete genetic variation and thereby their evolutionary benefits. We examined the genetic basis of three sexually selected morphometric traits in bighorn sheep (): horn length, horn base circumference, and body mass. These traits are of specific concern in bighorn sheep as artificial selection through trophy hunting opposes sexual selection. Specifically, horn size determines trophy status and, in most North American jurisdictions, if an individual can be legally harvested. Using between 7,994-9,552 phenotypic measures from the long-term individual-based study at Ram Mountain (Alberta, Canada), we first showed that all three traits are heritable ( = 0.15-0.23). We then conducted a genome-wide association study (GWAS) utilizing a set of 3,777 SNPs typed in 76 individuals using the Ovine Infinium HD SNP BeadChip. We found suggestive association for body mass at a single locus (OAR9_91647990). The absence of strong associations with SNPs suggests that the traits are likely polygenic. These results represent a step forward for characterizing the genetic architecture of fitness related traits in sexually dimorphic ungulates.
阐明与适应性相关性状的遗传基础是分子生态学的一个主要目标。受性选择影响的性状尤其令人感兴趣，因为非随机的配偶选择应该会消耗遗传变异，从而影响其进化益处。我们研究了大角羊的三个受性选择的形态特征的遗传基础：角长、角基部周长和体重。在大角羊中，这些特征特别值得关注，因为通过战利品狩猎进行的人工选择与性选择相悖。具体而言，角的大小决定了战利品的地位，并且在大多数北美司法管辖区，还决定了个体是否可以合法捕猎。利用来自加拿大艾伯塔省拉姆山基于个体的长期研究中的7994 - 9552个表型测量数据，我们首先表明这三个特征都是可遗传的（遗传力 = 0.15 - 0.23）。然后，我们利用一套在76个个体中使用绵羊Infinium HD SNP芯片分型的3777个单核苷酸多态性（SNP）进行了全基因组关联研究（GWAS）。我们在一个单一基因座（OAR9_91647990）发现了与体重的潜在关联。与SNP缺乏强关联表明这些性状可能是多基因的。这些结果代表了在表征两性异形有蹄类动物中与适应性相关性状的遗传结构方面向前迈出的一步。
