DISSERTATION RESEARCH: Landscape genetics and connectivity in a polymorphic salamander, Plethodon cinereus

该项目将研究在不同种群中维持颜色多态的生态和进化因素，东方红背火蜥蜴是一种具有红色和黑色条纹以及无条纹黑色实心形态的物种。自然界中的许多物种都有在一个种群中一起出现的多个颜色变形。然而，特定变形的发生频率在不同的人群中可能会有很大的差异。进化生态学中一个基本的悬而未决的问题是，这些差异主要是由自然选择还是物种分散造成的。这项研究将收集和分析32个东部红背火蜥蜴种群的基因组数据，这些种群的范围从只有一种颜色的变型到具有不同频率的两种变型。该物种的不同形态在生物学的其他方面也有所不同，如生理学和攻击性，一个主要目标是评估在维持形态频率方面种群之间局部适应与扩散的相对重要性。这些结果将加深我们对颜色变化和多样性进化之间关系的基本理解。此外，该项目将为本科生提供研究机会，他们将接受尖端基因技术的培训。外展活动包括在当地两个自然保护区举行的公开研讨会，以及在当地图书馆为学童举办的教育展览。该项目将使用基因组数据来确定地理距离、环境变量、变异频率或这些因素的组合是否最好地解释了东部红背蜥蜴(Plethodon Cinereus)的遗传变异模式。遗传数据将使用双酶切限制相关DNA(DdRAD)收集。这些数据将被用来量化来自俄亥俄州北部32个种群的480个个体的基因流水平，这些群体的变异频率从单态到不同程度的多态。各种统计分析，如结构、BAYESCAN和冗余分析，将被用来确定灰霉菌的遗传变异是否与表型频率或地理距离更紧密地联系在一起。总体而言，本研究将提供有关变异频率和地理距离对解释灰霉菌遗传变异模式的相对贡献的关键信息，并将加深我们对参与颜色多态进化和维持的因素的理解。

This project will investigate the ecological and evolutionary factors that maintain color polymorphism in different populations of the Eastern Red-backed Salamander, a species that has a 'striped' red and black morph and an 'unstriped' solid black morph. Many species in nature have multiple color morphs that occur together within a single population. However, the frequencies at which particular morphs occur can vary widely among different populations. A fundamental unanswered question in evolutionary ecology is whether natural selection or dispersal is primarily driving these differences. This study will collect and analyze genomic data from 32 Eastern Red-backed Salamander populations that range from having only a single color morph present to having both morphs present at various frequencies. Different morphs of this species also differ in other aspects of their biology, such as physiology and aggression, and a major goal is to assess the relative importance of local adaptation versus dispersal among populations in maintaining morph frequencies. Results will further our basic understanding of the relationship between color variation and the evolution of diversity. In addition, the project will provide research opportunities for undergraduate students, who will be trained in cutting-edge genetic techniques. Outreach includes public seminars at two local nature preserves and educational displays at the local library for school children.This project will use genomic data to determine whether geographic distance, environmental variables, morph frequency, or a combination of these factors best explain patterns of genetic variation in the Eastern Red-backed Salamander, Plethodon cinereus. Genetic data will be collected using double digest restriction associated DNA (ddRAD). These data will be used to quantify levels of gene flow in P. cinereus from 480 individuals from 32 populations across northern Ohio that vary in morph frequency, from monomorphic to various degrees of polymorphic. A variety of statistical analyses, such as STRUCTURE, BAYESCAN, and redundancy analysis, will be used to determine if genetic variation in P. cinereus is more closely linked with phenotype frequency or geographic distance. Overall, this study will provide critical information on the relative contributions of morph frequency and geographic distance for explaining patterns of genetic variation in P. cinereus, and will improve our understanding of the factors involved in the evolution and maintenance of color polymorphisms.