DISSERTATION RESEARCH: Mate choice, genetic variation and population structure in hybrid zones

行为决定是防止物种杂交的重要机制，对自然杂交物种的进化命运至关重要。该项目旨在了解这些行为决定如何影响种群的遗传。两种新热带河流鱼类之间DNA序列的单核苷酸差异将被用于研究墨西哥一个地区两种鱼类在野外杂交的杂交种群的遗传学。由于杂交鱼类有时难以从视觉上与亲本物种区分开来，这种分子方法将使研究人员能够识别鱼类是杂交物种还是亲本物种。了解个体的物种身份将使研究人员能够通过确定雌性与谁交配（配偶选择决定）和个体与谁共度时间（社会决定）来检查行为决定，以及在这些活着的鱼中，杂交鱼和纯亲本鱼的出生后存活率是否存在差异。初步结果表明，在形成种群遗传方面，行为决定可能比对杂交鱼的选择更重要。进一步的分子研究将允许对行为和遗传模式进行更深入的分析。这项工作将在理解交配前行为（社会决定和配偶选择决定）和交配后行为（卵子的差异受精和自然选择）对自然杂交种的命运、物种的生殖隔离和物种形成的贡献的基础上建立和扩展。除了继续促进国际合作项目外，该项目和调查人员还将通过墨西哥的CICHAZ实地站，通过电子媒体和指导一名墨西哥学生学习分子技术，完成外联工作。

Behavioral decisions are important mechanisms that can prevent interbreeding of species, and are critical to the evolutionary fate of natural hybrids. The project seeks to understand how these behavioral decisions affect the genetics of populations. Single nucleotide differences in DNA sequences between two species of neotropical stream fish will be used to study the genetics of hybrid populations in an area of Mexico where the two species hybridize in the wild. Since hybrid fish are sometimes difficult to visually distinguish from parent species, this molecular approach will enable investigators to identify fish as hybrid or parent species. Knowing the species identity of individuals will allow the investigators to examine behavioral decisions by determining who females mate with (mate choice decisions) and who individuals spend time with (social decisions), as well as whether there are differences in post-birth survival among hybrids and pure parentals in these livebearing fish. Preliminary results suggest that behavioral decisions may be more important in shaping the genetics of populations than is selection against hybrid fish. Further molecular work will allow more in-depth analyses of behavior and genetic patterns. This work will build and expand upon understanding the contributions of both pre-mating behavior (social decisions and mate choice decisions) and post-mating behavior (differential fertilization of eggs and natural selection) to the fate of natural hybrids, reproductive isolation of species and speciation. The project and investigators will accomplish outreach through the CICHAZ field station in Mexico via electronic media and mentoring of a Mexican student in molecular techniques in addition to continuing to foster internationally collaborative projects.