Genomic analysis of fitness-related traits in bighorn sheep

我的研究目的是确定决定野生大角羊性状变异的基因。为了做到这一点，我的研究小组将通过广泛利用现有的近缘关系家羊的基因组数据，并通过开发新的大角羊基因组资源，来开发大角羊基因组的高密度图谱。我的团队将为大角绵羊开发一系列5000个单核苷酸多态(SNP)标记并对其进行基因分型，并使用这些标记在两个野生群体中定位与体重、角大小、寿命和气质等特征相关的基因。在这样做的过程中，我们将更好地了解性状变异的遗传结构(基因的数量、它们的作用及其相互作用)。利用这些信息，我们可以评估人工选择和自然选择对遗传变异的影响，以发展对人类活动对野生动物进化影响的更广泛和更一般的理解。在一个种群中，我们将研究40年的战利品狩猎对角大小和体重的遗传变异的影响。我们将测试这一假设，即战利品狩猎对角生长的遗传变异产生了不利影响，从而通过改变种群中角生长等位基因的频率导致角较短的公羊进化。在第二个种群中，我们将检验这样一种假设，即通过故意将新移民引入与世隔绝的种群而实现的“基因拯救”，是由移民携带的新基因变异的导入造成的，这些变异随后受到自然选择的青睐。这项工作的结果将对我们基本理解野生动物表型变异的本质(例如，我们观察到的变异中有多少是由几个大效应基因造成的)都是重要的。以及与人类活动的进化后果有关的更具体的问题(例如，收获是否对目标人群的基因库产生不利影响？)。

The aim of my research is to identify the genes that determine trait variation in wild bighorn sheep. To do this, my research group will develop a high density map of the bighorn sheep genome by making extensive use of existing genomic data from closely related domestic sheep and by developing new genomic resources for bighorn sheep. My group will develop and genotype an array of 5,000 single nucleotide polymorphism (SNP) markers for bighorn sheep and use these to map the genes associated with traits such as body weight, horn size, longevity and temperament in two wild populations. In doing this, we will gain a better understanding of the genetic architecture (the number of genes, their action, and their interactive effects) of trait variation. Using this information, we can assess the impact of both artificial and natural selection on genetic variation to develop a broader and more general understanding of the evolutionary impact of human activity on wildlife. In one population, we will study the impact of 40 years of trophy hunting on genetic variation for horn size and body weight. We will test the hypothesis that trophy hunting has adversely affected genetic variation for horn growth, therefore leading to the evolution of rams with shorter horns by changing the frequency of horn growth alleles in the population. In a second population, we will test the hypothesis that a "genetic rescue", accomplished by the deliberate introduction of new migrants to an isolated population, was caused by the introgression of new genetic variants carried by the migrants which were subsequently favoured by natural selection. The outcomes of this work will be important both for our basic understanding of the nature of phenotypic variation in wildlife (e.g. how much of the variation that we observe is due to a few genes of large effect?) as well as for more specific questions related to the evolutionary consequences of human activity (e.g. does harvesting adversely affect the gene pool of the target population?).