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

该项目将研究维持东部红背蝾螈不同种群颜色多态性的生态和进化因素，该物种具有“条纹”红色和黑色变形和“无条纹”纯黑色变形。自然界中的许多物种都有多种颜色变形，这些变形在一个种群中同时发生。然而，特定变形发生的频率在不同人群中可能存在很大差异。进化生态学中一个尚未解答的基本问题是，自然选择还是扩散是造成这些差异的主要原因。这项研究将收集并分析 32 个东部红背蝾螈种群的基因组数据，这些种群的范围从仅存在单一颜色变体到以不同频率出现两种颜色变体。该物种的不同形态在生物学的其他方面也有所不同，例如生理学和攻击性，主要目标是评估局部适应与种群间扩散在维持形态频率方面的相对重要性。结果将进一步加深我们对颜色变化与多样性进化之间关系的基本理解。此外，该项目还将为本科生提供研究机会，他们将接受尖端遗传技术的培训。外展活动包括在当地两个自然保护区举办公开研讨会，以及在当地图书馆为学童举办教育展览。该项目将使用基因组数据来确定地理距离、环境变量、变形频率或这些因素的组合是否能最好地解释东部红背蝾螈（Plethodon cinereus）的遗传变异模式。将使用双消化限制性相关 DNA (ddRAD) 收集遗传数据。这些数据将用于量化俄亥俄州北部 32 个群体的 480 个个体的灰白假单胞菌的基因流水平，这些个体的形态频率各不相同，从单态性到不同程度的多态性。各种统计分析，例如结构、贝叶斯扫描和冗余分析，将用于确定灰葡萄球菌的遗传变异是否与表型频率或地理距离更密切相关。总体而言，这项研究将为解释灰葡萄球菌遗传变异模式提供有关形态频率和地理距离的相对贡献的关键信息，并将提高我们对颜色多态性进化和维持所涉及因素的理解。

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.