The evolutionary genetics of reinforcement: an empirical study in neotropical Costus

理解自然选择在物种起源中的作用是进化生物学的中心目标。种群遗传学理论表明，在特殊情况下，自然选择可以加强生活在同一地理区域的新近分化物种之间的繁殖障碍，但这一理论尚未得到自然系统数据的充分解决。本项目在一个快速物种形成的热带植物群体中研究了这一过程的进化遗传学，先前的研究已经发现了生殖障碍加强的证据。该研究使用遗传作图技术来描述性状的遗传基础和两个新近分化物种的生殖隔离机制，通过实地实验来更好地了解这些性状的生态后果，并使用分子标记来评估物种之间基因流动的历史模式。自然选择可以直接促进物种形成的观点很重要，因为它显示了适应过程和物种形成之间的直接联系，因为它阐明了在没有长时间地理隔离的情况下发生多样化的途径。本研究从经验上探讨了在何种情况下，选择能够以一种综合的方式加强物种形成，将生态因素和潜在的遗传过程联系起来。研究结果将广泛适用于理解某些生物群体和地理区域是如何在没有长时间或地理隔离的情况下多样化的。该项目将培训分子遗传学和进化方面的年轻科学家，并为他们提供在热带雨林进行实地研究的机会。

Understanding the role that natural selection plays in the origin of species is a central goal of evolutionary biology. Population genetics theory shows that, in special circumstances, natural selection can reinforce reproductive barriers between recently diverged species living in the same geographic area, but this theory has not been adequately addressed with data from natural systems. This project examines the evolutionary genetics of this process in a rapidly speciating group of tropical plants for which prior research has found evidence of reinforcement of reproductive barriers. The research uses genetic mapping techniques to characterize the genetic basis of the traits and mechanisms that reproductively isolate two recently diverged species, field experiments to better understand the ecological consequences of those traits, and molecular markers to assess historical patterns of gene flow between the species.The idea that natural selection can directly favor speciation is important, because it shows a direct link between the processes of adaptation and speciation and because it elucidates a route for diversification to occur without prolonged periods of geographic isolation. This research empirically addresses the circumstances under which selection can reinforce speciation in a comprehensive way that links ecological factors and the underlying genetic processes. The results will be broadly applicable to understanding how certain groups of organisms and geographic areas have diversified without long periods of time or geographic isolation. The project will train young scientists in molecular genetics and evolution, and provide opportunities for them to conduct field research in a tropical rainforest.