DISSERTATION RESEARCH: Investigating the Joint Effects of Phylogeny and Adaptation on Phenotypic Variation at a Continental Scale (Serpentes:Thamnophis)

论文研究：研究系统发育和适应对大陆尺度表型变异的联合影响（蛇类：Thamnophis）

• 批准号: 1600884
• 负责人: Adam Leache
• 金额: $ 2.01万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1600884&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Investigating; Joint; Effects

Local adaptation is a hallmark of geographically variable species with wide distributions that span geographic barriers to gene flow. Determining the underlying population structure upon which to place these local adaptations is a central objective in evolutionary biology. However, the impact of evolutionary history on inference of contemporary population structure has been largely unexplored. This research aims to examine the effects of evolutionary history on genetic and morphological variation among populations at regional and continental scales. Empirical data and the results from this study will serve as a model for teaching evolution, specifically genetic drift, in both academic and public settings. Extensive phenotypic variation between widespread organisms often complicates determination of taxonomic relationships. The range of the common garter snake Thamnophis sirtalis spans all of North America, excluding Mexico and the desert southwest. Twelve T. sirtalis subspecies are currently recognized and defined by color patterning. One of these subspecies, T.s. pickeringii, co-occurs with two less widely distributed congeners (T. elegans and T. ordinoides) in the Pacific Northwest across the San Juan Archipelago. This region was subject to multiple Pleistocene glaciation events up until ~20,000 years ago, after which flora and fauna recolonized the islands from neighboring mainland refugia. This project aims to investigate the relationship between evolutionary history and contemporary population variation by comparing simulated data of known demographic histories to genomic data from two empirical study systems: 1) the young San Juan Archipelago Thamnophis species assemblage, 2) a continental-scale sampling of all Thamnophis sirtalis subspecies. These two systems occur in proximity to multiple known Pleistocene refugia and across geographic barriers to gene flow for other North American flora and megafauna, but it is unclear whether a generalist ectotherm will show the patterns observed in previous phylogeographic studies. Using genomic data, this project will test whether 1) T. sirtalis subspecies designations (and therefore phenotypes) represent unique evolutionary lineages, 2) distinct evolutionary lineages within T. sirtalis occur along known or novel barriers to gene flow, or 3) the combined effects of historical vicariance and non-uniform selective forces across different subspecies produce a signal discordant with phenotypic variation.

局部适应是地理上可变物种的标志，其分布范围很广，涵盖了基因流的地理障碍。确定将这些局部适应的基本人口结构是进化生物学的核心目标。但是，进化史对当代人口结构的推断的影响在很大程度上尚未探索。这项研究旨在检查进化史对地区和大陆尺度人群中遗传和形态变异的影响。经验数据和这项研究的结果将成为学术和公共环境中教学进化，特别是遗传漂移的模型。广泛的生物之间的广泛表型变化通常会使分类关系的确定得以复杂化。普通的吊蛇蛇thamnophis sirtalis的范围遍布北美，不包括墨西哥和西南沙漠。目前，十二个T. sirtalis亚种被颜色图案识别和定义。这些亚种之一，T.S。 Pickeringii，与圣胡安群岛（San Juan Archipelago）西北太平洋地区的两个分布不太分布的同类物（T.秀素和T. Ordinoides）的同事。直到大约20，000年前，该地区都经历了多个更新世的冰川事件，此后，动植物将植物从邻近的大陆雷德吉亚（Refugia）重新殖民。该项目旨在通过将已知人口统计学历史的模拟数据与来自两个经验研究系统的基因组数据进行比较，研究进化史与当代种群变化之间的关系：1）年轻的圣胡安群岛thamnophis物种组合，2）所有thamnnophis sirtalissirtalisspecies的大陆规模采样。这两个系统出现在靠近多个已知的更新世避难所以及其他北美植物群和大型群岛基因流动的地理障碍中，但是尚不清楚通才的阶级是否会显示在先前的植物地球学研究中观察到的模式。使用基因组数据，该项目将测试1）sirtalis亚种的名称（以及表型）是否代表独特的进化谱系，2）t. sirtalis内的不同进化谱系沿着已知的或新颖的基因流动或新颖的障碍，或者3）跨基因流动效果产生了跨不同的分子差异的综合作用。