Speciation and Phylogenetic Diversification in a Polytypic Amphibian

Shaffer博士将检查该过程，以及 物种形成和分化的模式， 变异极大的北美虎蝾螈。 项目 有两个基本目标。 首先，它使用了一系列新的 从分子生物学中收集DNA序列数据的技术 来自北美和墨西哥的蝾螈种群。 序列数据将用于确定系统发育 蝾螈的关系，使用相似性模式 和DNA的差异作为一个共同的 祖先 这些结果将补充以前的研究 Shaffer博士进行的关于 虎蝾螈，并将回答基本问题， 在这片大陆上， 分布的物种 Shaffer博士还将研究这一机制， 遗传分化已经进化。 为此， 将进行实验，量化在何种程度上， 在田间缺乏杂交育种可归因于以下两种情况之一：1） 交配后发生的发育异常，或2） 不同人群之间的行为差异 可能会互相求爱交配 通过连接这个 机械方法与分子描述的 进化模式的分化，研究将 提供了一个独特的，深入分析物种形成如何发生在 分布广泛的脊椎动物物种。

Dr. Shaffer will examine the process, as well as the pattern, of speciation and differentiation in the wide-ranging, extremely variable North American Tiger salamanders. The project has two fundamental objectives. First, it uses a new series of techniques from molecular biology to collect DNA sequence data from salamander populations from across North America and Mexico. The sequence data will be used to determine the phylogenetic relationships of the salamanders, using patterns of similarity and differences in DNA as an indicator of recency of common ancestry. These results will complement previous research conducted by Dr. Shaffer on the phylogenetic relationships of tiger salamanders and will answer fundamental questions on how genetic diversification has occurred in this continentally distributed species. Dr. Shaffer will also examine the mechanisms by which this genetic differentiation has evolved. To do so, breeding experiments will be conducted that quantify the extent to which a lack of interbreeding in the field is attributable to either 1) developmental abnormalities that occur after mating, or 2) behavioral differences between populations that make them less likely to court and mate with one another. By interfacing this mechanistic approach with the molecular description of the evolutionary pattern of differentiation, the research will provide a unique, in-depth analysis of how speciation occurs in wide-ranging vertebrate species.