SG: Collaborative Research: A genomic analysis of the impact of genetic divergence, and chromosomal rearrangement on introgression in replicate Fundulus hybrid zones

当不同物种的成员试图繁殖时，就会发生杂交。虽然传统上认为杂交对物种完整性和物种形成过程通常无关紧要(由于某些原因，杂交被认为是不可行的)，但越来越多的证据表明，在某些情况下，它实际上可能是有益的，并加速物种形成。要了解生物多样性的起源，需要对可能改变杂交结果的机制有更全面的了解。一种这样的机制是染色体的重排，这可能会以限制杂交潜力的方式改变物种的基因组结构。该项目将研究一种模式鱼类--金枪鱼，以了解分化和染色体重排如何相互作用，以确定自然产生的杂交区的动态。这项研究还将用于高中课程的开发，以教授进化论概念，并为本科生提供研究经验。在Fundulus notatus物种复合体中的Topminnos在密西西比河流域和墨西哥湾北部的大部分流域都有广泛重叠的范围。早期对这些物种的研究发现了一些复制的杂交区，在这些杂交区中，杂交物种和种群的分化程度不同，在某些情况下，染色体数量也不同。研究人员将使用现代基因组学工具来量化八个复制杂交区的杂交数量和渗透模式。实验室中的人工育种实验将产生后代，这将有助于制作杂交种群的遗传图谱。遗传图谱将阐明复制杂交区中基因流动的空间模式。试验性的杂交区试验还将检查配偶选择的动态和杂交后代的生存能力。

Hybridization occurs when members of different species attempt to reproduce. While hybridization has traditionally been viewed as normally inconsequential to species integrity and the speciation process (hybrids were assumed to be inviable for some reason), there is growing evidence it may actually be beneficial and accelerate speciation under some circumstances. Understanding the origins of biodiversity requires more thorough knowledge of mechanisms that may alter the outcome of hybridization. One such mechanism is the rearrangement of chromosomes that may change the genomic structure of species in a way that limits the potential for hybridization. This project will study a model fish species, topminnows, in order to understand how divergence and chromosomal rearrangements may interact to determine the dynamics of naturally occurring hybrid zones. The research will also be used in development of high school curricula to teach evolutionary concepts and to provide research experiences for undergraduates. Topminnows in the Fundulus notatus species complex have broadly overlapping ranges throughout much of the Mississippi River basin and northern Gulf of Mexico drainages. Earlier work with these species identified a number of replicate hybrid zones where the hybridizing species and populations differ in levels of divergence and, in some cases, chromosome number. The researchers will use modern genomic tools to quantify the amount of hybridization and patterns of introgression in eight replicate hybrid zones. Artificial breeding experiments in the laboratory will produce progeny that will facilitate the production of genetic maps of hybridizing populations. Genetic maps will elucidate spatial patterns of gene flow in replicate hybrid zones. Experimental hybrid zone trials will also examine mate choice dynamics and the viability of hybrid offspring.