Barriers to Intraspecific Gene Flow Among Highly Divergent Salamander Lineages

本研究详细探讨了分布广泛的斑点蝾螈（Ambystoma maculatum）两个高度不同的遗传谱系之间有限的基因交换模式和过程。在更新世的气候周期中，斑点蝾螈种群被隔离在两个独立的避难所，导致了高度分化的遗传种族。这些种群后来扩大了它们的活动范围，形成了不同年龄和地理重叠的接触带。本提案的主要目标是利用核DNA标记和收集的三个接触区来评估遗传分离和随后的再接触的遗传后果。交配实验将用于量化交配选择的模式和发生在谱系之间的基因交换（或缺乏）的程度。生殖隔离的研究对我们理解分化和物种形成至关重要。物种内部谱系的分化可以作为早期物种形成的例子，因此有助于我们理解最终导致新物种产生和生物多样性产生的过程。这项研究还对物种保护具有启示意义，因为它记录了一个广泛存在的物种的遗传多样性分布；对解释生境破碎化的遗传后果和该分类群和其他分类群的新接触带至关重要的信息。

This research examines in detail the patterns and processes of limited gene exchange between two highly divergent genetic lineages in the widespread spotted salamander (Ambystoma maculatum). During the climatic cycles of the Pleistocene, spotted salamander populations were isolated in two independent refugia, resulting in highly divergent genetic races. These populations have subsequently expanded their ranges, resulting in contact zones of different ages and geographical overlap. The main goal of this proposal is to assess the genetic consequences of genetic isolation and subsequent re-contact using nuclear DNA markers and collections along three of these contact zones. Mating experiments will be used to quantify patterns of mate choice and the degree of genetic exchange (or lack thereof) that occur between the lineages.Studies of reproductive isolation are critical to our understanding of differentiation and speciation. Divergence among lineages within species can be examples of incipient speciation and therefore help us understand the process that ultimately leads to novel species and the generation of biodiversity. This research also has implications for conservation because it documents the distribution of genetic diversity in a widespread species; information crucial to interpreting the genetic consequences of habitat fragmentation and new contact zones in this and other taxa.