Behavioral and evolutionary causes of within-population assortative mating in threespine stickleback

项目描述：当个体选择与自己更相似的伴侣时，就会出现正选型交配。最近一项对1000多个案例研究的分析发现，在人类和非人类动物中，积极的选型交配是一种规律，而不是例外。积极的分类交配维持了种群中的遗传变异，使遗传作图研究（例如，寻找致病基因）产生偏差，并可能推动新物种的起源。鉴于选择性交配的重要遗传影响，令人惊讶的是，人们对其行为和进化原因知之甚少。研究者将进行实验来检验关于为什么积极交配进化的竞争性假设。具体而言，本研究将(1)评估一种重要模式生物（三刺棘鱼，棘鱼）的20个种群内的分类交配频率和强度，(2)确定产生分类的配偶选择行为，(3)测试分类是否受到直接选择和间接选择的青睐，以及/或不受成本或信号传递障碍的影响。值得注意的是，这项工作为长期存在的破坏性自然选择倾向于积极的分类交配理论提供了第一个基于现场的实证检验。这一假设如果成立，将改变我们对新物种如何产生的看法。更广泛的意义：该项目将提高我们对选择性交配的原因和发生率的理解。通过关注这种形式的非随机交配，这项工作将提高人们对高频率分类的认识，因此需要在进化生物学和医学的遗传和关联图谱研究中考虑非随机交配。此外，该项目还将把科学家与高中生物教师和在职教师配对。这将为K-12科学教师提供生物学研究的实践经验，并促进科学家与现任和未来教师之间的交流。

Project description: Positive assortative mating occurs when individuals select mates who are more similar to themselves than expected by chance. A recent analysis of more than 1,000 case studies found that positive assortative mating is the rule rather than the exception within human and non-human animals. Positive assortative mating maintains genetic variation in populations, biases genetic mapping studies (e.g., to find disease-causing genes), and may drive the origin of new species. In light of the important genetic effects of assortative mating, it is surprising that little is known about its behavioral and evolutionary causes. The investigator will conduct experiments to test competing hypotheses as to why positive mating evolves. Specifically this study will (1) evaluate the frequency and strength of assortative mating within 20 populations of an important model organism (the threespine stickleback, Gasterosteus aculeatus), (2) identify the mate-choice behaviors that generate assortment, and (3) test whether assortment is favored by direct versus indirect selection, and/or disfavored by costs or barriers to signal transmission. Notably, this work provides the first field-based empirical test of the long-standing theory that disruptive natural selection favors positive assortative mating. This hypothesis, if true, would change our view about how new species arise.Broader significance: The project will improve our understanding of the causes and incidence of assortative mating. By focusing attention on this form of non-random mating, the work will increase awareness of the high frequency of assortment and therefore the need to account for non-random mating in genetic and association mapping studies in both evolutionary biology and medicine. In addition, the project will pair scientists with high-school biology teachers and pre-service teachers-in-training. This will give K-12 science teachers practical experience in biological research, and foster communication between scientists and current and future teachers.