Dissertation Research: An investigation of isolating mechanisms between sister species in the genus Empidonax

对新物种形成过程的研究仍然是进化生物学研究的一个活跃领域。当不同生物群体之间的基因交流出现障碍时，新物种就形成了。当密切相关的物种在地理重叠区域相互作用时，可以测试特定类型屏障的强度。本项目研究了两种密切相关的北美鸣禽之间基因交换的两个重要潜在障碍的强度。太平洋斜坡捕蝇鸟和科迪勒兰捕蝇鸟对栖息地的偏好在它们的大部分活动范围内都不同，鸣叫也不同，这是选择配偶的一个重要特征。它们同时出现在两个领域。在一个地区，基因交换相对普遍，而在另一个地区则受到限制。本研究将基于gis的生物气候分析和交配行为的实验测试与遗传分析相结合，探讨生境偏好和交配行为的差异对基因交换的影响。本研究采用综合方法研究新物种形成的关键过程。两个具有不同进化动力的地理接触区域的存在为比较不同基因交换障碍的相对优势提供了一个独特的机会。研究表明，稀有或濒危物种与近亲之间的基因交换可能产生负面影响，因此了解调节近亲物种之间基因交换的因素具有重要的保护意义。作为研究计划的一部分，拓展活动将涉及K-12学生和本科生。

Examination of the processes involved in the formation of new species remains an active area of investigation in evolutionary biology. New species form when barriers to the exchange of genes arise between groups of organisms. The strength of specific types of barriers can be tested when closely related species interact in areas of geographic overlap. This project examines the strength of two important potential barriers to genetic exchange between two closely related North American songbirds. Pacific-slope flycatchers and Cordilleran flycatchers differ in habitat preference across much of their ranges and differ in song, a trait important in mate choice. They co-occur in two areas. In one area, genetic exchange is relatively common, whereas in the other it is restricted. By combining GIS-based bioclimatic analysis and experimental tests of mating behavior with genetic analysis, this study will examine the effects of differences in habitat preference and mating behavior on the exchange of genes. This study utilizes an integrated approach to investigate key processes involved in the formation of new species. The existence of two areas of geographic contact with differing evolutionary dynamics presents a unique opportunity to compare the relative strengths of different barriers to gene exchange. Understanding the factors that regulate the exchange of genes between closely related species has important conservation implications, as research has demonstrated potentially negative consequences of genetic exchange between rare or threatened species and close relatives. Outreach activities will involve K-12 students and undergraduates will be mentored as part of the research plan.