SG: Collaborative Research: A genomic analysis of the impact of genetic divergence, and chromosomal rearrangement in 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。虽然杂交通常被认为对物种完整性和物种形成过程无关紧要（由于某种原因，杂交被认为是不可生存的），但越来越多的证据表明，在某些情况下，杂交实际上可能是有益的，并加速了物种的形成。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。其中一种机制是染色体的重排，它可能以某种方式改变物种的基因组结构，从而限制杂交的潜力。该项目将研究一种模式鱼类——顶米诺鱼，以了解分化和染色体重排如何相互作用，从而确定自然发生的杂交带的动态。这项研究还将用于开发高中课程，教授进化概念，并为本科生提供研究经验。在诺图斯底物种复合体中，顶鲦鱼在密西西比河流域和墨西哥湾北部的排水系统中有广泛的重叠范围。早期对这些物种的研究发现了许多复制杂交区，在这些杂交区中，杂交物种和种群的分化水平不同，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工具来量化杂交的数量和8个重复杂交区的渗入模式。实验室中的人工育种实验将产生后代，这将有助于杂交群体遗传图谱的制作。遗传图谱将阐明重复杂交区基因流动的空间格局。实验杂交区试验也将检查配偶选择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.