DISSERTATION IMPROVEMENT GRANT: Identifying Reproductive Isolation Loci from Clines in Hybrid Zones

对于进化生物学家和非科学家来说，新物种的出现是一个引人入胜的话题。物种形成是指种群间的遗传差异累积，称为不亲和性，降低了来自不同种群的双亲后代的适合度。这项研究将开发新的方法来分析物种形成过程中不相容的基因组签名。在理解物种形成的遗传基础方面的进展将促进野生动物保护、作物改良以及最近人类和尼安德特人杂交、人类进化和医学遗传学的努力。开发的软件和方法将免费提供，并为对其他分类群进行类似研究提供指导。这笔赠款还促进了与一名德国研究人员的国际合作，以及为第一代大学毕业生提供的博士论文研究培训。最后，物种形成是理解进化过程的基础。研究人员定期参加外联活动，包括为K-12教师和学生举办的公开讲座和活动。在物种形成过程的早期，不相容是不常见的，种群可能会在一个称为杂交区的区域交叉。这类杂交区为寻找不亲和性和了解物种形成过程提供了难得的机会。不幸的是，杂交区的不亲和性分析受到目前可用于分析最近可用的基因组数据的方法的限制。这项任务因种群的历史因素而变得复杂，这些种群模仿或掩盖了针对基因组序列中的杂交种进行选择的效果。小鼠亚种复合体Mus Musculus spp.为在自然杂交区研究实验室定位的杂交不亲和性基因座提供了一个独特的机会。许多杂交不亲和性基因座已被定位于肌肉分枝杆菌和家养分枝杆菌的实验室杂交。这两个物种还在中欧形成了一个稳定的杂交区域。该项目将使用临床方法来测试在实验室杂交中发现的杂交不亲和性基因座是否显示出小鼠杂交区的基因流减少。由于目前的分析方法没有很好地设计来检测实验室研究中发现的那种等位基因之间的相互作用，也没有考虑杂交区复杂的人口统计因素，所以这项研究包括对杂交区分离的杂交不亲和性的计算机模拟，并使用现有的方法以及作为该项目的一部分开发的方法来衡量它们对克隆体的影响。新方法将通过实地研究进行测试。

The emergence of new species from others is a captivating topic for evolutionary biologists and non-scientists alike. Speciation occurs when genetic differences called incompatibilities accumulate between populations reducing the fitness of progeny of parents from different populations. This research will develop new approaches to analyze genomic signatures of incompatibilities during the process of speciation. Progress in understanding the genetic basis of speciation will improve efforts in wildlife conservation, crop improvement, and given recent evidence that humans and Neanderthals interbred, human evolution and medical genetics. The software and approaches developed will be freely available and provide guidance for similar studies conducted on other taxa. This grant also facilitates an international collaboration with a German researcher, and doctoral dissertation research training for a first generation college graduate. Finally, speciation is a topic that is fundamental to understanding the process of evolution. The researchers regularly participate in outreach events including public lectures and events for K-12 teachers and students. Early in the process of speciation incompatibilities are uncommon and populations may cross in a region called a hybrid zone. Such hybrid zones provide rare opportunities to search for incompatibilities and to understand the speciation process. Unfortunately, analysis of incompatibilities in hybrid zones is limited by the methods currently available for analyzing recently available genomic data. The task is complicated by historical factors of populations that mimic or mask the effects of selection against hybrids in genome sequences. The mouse subspecies complex, Mus musculus spp., offers a unique opportunity to study laboratory mapped hybrid incompatibility loci in a natural hybrid zone. Numerous hybrid incompatibility loci have been mapped in laboratory crosses between M. m. musculus and M. m. domesticus. These two species also form a stable hybrid zone in central Europe. This project will use cline methods to test whether hybrid incompatibility loci discovered in laboratory crosses exhibit reduced gene flow in the mouse hybrid zone. Because current analytical methods are not well designed to detect interactions between alleles of the kind found in the laboratory studies and do not consider the complex demographic factors of hybrid zones, the research includes computer simulations of hybrid incompatibilities segregating in hybrid zones and measures their effects on clines using currently available methods, as well as methods developed as part of this project. The new methods will be tested by the field studies.