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

该项目将调查在东部红背蝾螈的不同种群中保持颜色多态性的生态和进化因素，这种物种具有“条纹”红色和黑色形态和“无条纹”黑色形态。自然界中的许多物种都有多种颜色变体，这些颜色变体在单个种群中一起出现。然而，特定变体出现的频率在不同人群中可能差异很大。进化生态学中一个尚未回答的基本问题是，究竟是自然选择还是扩散导致了这些差异。这项研究将收集和分析来自32个东部红背蝾螈种群的基因组数据，这些种群的范围从只有一种颜色变体到两种变体都以不同的频率存在。该物种的不同变体在其生物学的其他方面也有所不同，例如生理学和侵略性，主要目标是评估在维持变体频率方面，当地适应与种群间扩散的相对重要性。研究结果将进一步加深我们对颜色变异与多样性演化关系的基本认识。此外，该项目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。该项目将利用基因组数据来确定地理距离、环境变量、变体频率或这些因素的组合是否最能解释东部红背蝾螈的遗传变异模式。将使用双消化限制性内切酶相关DNA（ddRAD）采集遗传数据。这些数据将用于量化来自北方俄亥俄州32个种群的480个个体的灰盖侧耳基因流水平，这些个体的形态频率从单态到不同程度的多态性不等。将使用各种统计分析，如结构，贝叶斯分析和冗余分析，以确定灰盖菇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，这项研究将提供关键信息的相对贡献的形态频率和地理距离的解释模式的遗传变异在P. cinereus，并将提高我们的理解的因素参与的进化和维护的颜色多态性。

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.