Dissertation Research: A Hybrid Zone Lens on Rapid Speciation During Refugial Isolation in the Field Vole (Microtus agrestis)

论文研究：田鼠（Microtus agrestis）避难隔离期间快速物种形成的混合区透镜

• 批准号: 1601050
• 负责人: Jeremy Searle
• 金额: $ 2万
• 依托单位: Cornell University
• 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: 2016-07-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1601050&HistoricalAwards=false
• 关键词: Dissertation; Research; Hybrid; Zone; Lens

Hybrid zones are natural laboratories that allow researchers to identify the changes that have caused populations to diverge into different, reproductively isolated species. This project will investigate a hybrid zone where two historically isolated populations of field voles now interbreed. Researchers will sample multiple individuals across the hybrid zone and identify the genomic regions involved in the formation of new species. One graduate student and a number of undergraduate students from diverse educational, cultural, and economic backgrounds will be trained in cutting-edge genetic techniques. This research will also be used as an active learning tool during a course specifically designed for first-year undergraduate students from historically underrepresented groups in the biological sciences. The vole genus, Microtus, is a model system to investigate the process of speciation because it has a diversification rate 60-100 times higher than other vertebrates. The distribution of genetic variation within the field vole (Microtus agrestis) has been heavily shaped by glacial cycles. The species includes distinct evolutionary lineages that survived in separate glacial refugia during recent glacial maxima and are highly differentiated. This research will focus on a hybrid zone between two of these lineages and use transcriptome sequencing to identify fixed genetic differences between them. These genomic regions will serve as targets for subsequent analyses of individuals from across the hybrid zone. Using genomic cline analyses that consider the genetic composition of individuals across this transect, researchers will characterize variation across the hybrid zone revealing loci that show restricted introgression. These loci will be considered candidate genes related to reproductive isolation responding to factors, such as selective differences associated with the differing environments of the hybridizing forms, and genetic incompatibilities between them. The results from these analyses will provide a conceptual and empirical groundwork for the genetic architecture underlying speciation driven by isolation in glacial refugia and provide a set of candidate loci to investigate speciation in other mammalian groups.

杂交区是天然的实验室，研究人员可以利用它来识别导致种群分化成不同的、生殖隔离的物种的变化。该项目将调查一个混合区，两个历史上孤立的田鼠种群现在在这里杂交。研究人员将对杂交区的多个个体进行采样，并确定参与新物种形成的基因组区域。来自不同教育、文化和经济背景的一名研究生和多名本科生将接受尖端遗传技术的培训。这项研究还将在专为生物科学领域历史上代表性不足群体的一年级本科生设计的课程中用作主动学习工具。田鼠属（Microtus）是研究物种形成过程的模型系统，因为它的多样化率比其他脊椎动物高 60-100 倍。田鼠（Microtus agrestis）内遗传变异的分布在很大程度上受到冰川周期的影响。该物种具有独特的进化谱系，在最近的盛冰期期间在单独的冰川避难所中生存，并且具有高度分化。这项研究将重点关注其中两个谱系之间的杂交区域，并使用转录组测序来识别它们之间固定的遗传差异。这些基因组区域将作为对整个杂交区域个体进行后续分析的目标。通过考虑该横断面个体的遗传组成的基因组细胞系分析，研究人员将描述整个杂交区的变异特征，揭示显示受限渗入的基因座。这些基因座将被视为与响应因素的生殖隔离相关的候选基因，例如与杂交形式的不同环境相关的选择性差异，以及它们之间的遗传不相容性。这些分析的结果将为冰川避难所隔离驱动的物种形成的遗传结构提供概念和经验基础，并提供一组候选基因座来研究其他哺乳动物群体的物种形成。