Quantitative Genetics and Phylogenetics

动植物的大多数可观察到的性状都受到许多遗传因素的影响。这类性状的遗传理论被称为数量遗传学。在过去的60年里，动物和植物育种家利用数量遗传学来改良家畜和作物品种。在过去的20年里，数量遗传学席卷了进化生物学，并彻底改变了我们对进化过程和现存物种谱系（系统遗传学）的理解。在进化时间尺度上应用定量遗传学理论时，需要假设遗传系统保持不变。为了对遗传的稳定性进行强有力的测试，人们需要对多个种群的遗传系统进行良好的估计，而这些种群又具有已知的进化关系。这些要求很难满足，因此尚未对继承的稳定性进行强有力的测试。目前的项目是建议使用吊带蛇和水蛇的自然种群进行这样一个强有力的测试。该建议的力量基于以下事实：(1)可以在每个种群中采样大量的家族，以对遗传进行良好的估计；(2)可以对多个种群和物种进行采样；(3)使用现代分子技术已经建立了种群和物种的系统发育关系。该提议的基本原理是，通过使用最适合进行遗传比较研究的自然蛇种群，人们可以检验进化研究中的一个关键假设，并可能揭示适用于所有动植物物种的遗传恒常原理。

Most of the observable traits of plants and animals are affected by many genetic factors. The theory for the inheritance of such traits is known as quantitative genetics. For the past 60 years, animal and plant breeders have used quantitative genetics to improve domestic animals and crop species. In the past 20 years, quantitative genetics has swept into evolutionary biology and is revolutionizing our understanding of evolutionary processes and the genealogy of living species (phylogenetics). In applying quantitative genetic theory on an evolutionary time scale, one needs to assume that the system of inheritance remains unchanged. To make a strong test for constancy of inheritance, one needs good estimates of the inheritance systems for multiple populations which, in turn, have known evolutionary relationships. These requirements are difficult to meet and so strong tests for constancy of inheritance have not yet been conducted. The current project is a proposal for such a strong test using natural populations of garter snakes and water snakes. The strength of the proposal rests on the facts that: (1) large numbers of families can be sampled in each population to give good estimates of inheritance, (2) multiple populations and species can be sampled and (3) the phylogenetic relationships of the populations and species have already been established using modern molecular techniques. The rationale of the proposal is that by using natural populations of snakes that are ideally suited for comparative studies of inheritance, one can test a key assumption in evolutionary studies and perhaps uncover a principle of genetic constancy that applies to all species of plants and animals.