Identifying Genetic Determinants of Speciation from Genomic Maps of Ancestry in Hybrid Mice

为什么会有这么多物种？一个物种形成两个物种的过程--物种形成--是生物多样性的主要决定因素。当物种在自然界中杂交时，它们的基因组的一些部分被交换，而另一些则没有。基因组中那些没有交换的区域使物种保持分离。通过识别老鼠物种中那些不相容的区域，这项研究将揭示导致物种形成(和生物多样性)的遗传机制。这项研究的另一个新贡献将是开发分析整个基因组的新方法，而不是一次分析一个区域。该项目将把研究与教师培训结合起来，与公众分享发现。除了扩展进化知识外，这项研究还将惠及包括人类健康在内的应用领域。例如，该项目中开发的框架可以用来理解当前人类与尼安德特人之间历史交配的生殖效应。这项研究将为测量杂交区域物种之间的基因流动提供新的理论和经验框架。焦点将是祖先连接--沿着染色体的那些点，祖先从一个物种切换到另一个物种。与现有的杂交基因组分析不同，这种方法很容易扩展到整个基因组。计算机模拟将被用来量化选择、迁徙和遗传漂移对整个基因组的祖先连接的影响。将对生殖隔离的一系列遗传结构进行调查，以确定针对杂交种叶片的选择可检测到基因组特征的条件。这一理论框架将被应用于在两个家鼠亚种之间的杂交中收集的新基因组数据，这两个亚种是研究物种形成的优秀模型。将确定造成新物种之间生殖障碍的不相容基因组区域。

Why are there so many species? The process by which two species are generated from one - speciation - is a major determinant of biodiversity. When species hybridize in nature, some parts of their genomes are exchanged and others are not. Those regions of the genome that are not exchanged keep the species separate. By identifying those incompatible regions in species of mice, this research will reveal genetic mechanisms responsible for speciation (and biodiversity). Another novel contribution of this research will be the development of new approaches that analyze entire genomes, instead of one region at a time. The project will combine research with teacher training to share discoveries with the public. In addition to expanding evolutionary knowledge, this research will benefit applied fields, including human health. For example, the framework developed in this project can be used to understand the current reproductive effects of historical mating between humans and Neanderthals.This research will provide new theoretical and empirical frameworks for measuring gene flow between species in hybrid zones. The focus will be ancestry junctions - those points along chromosomes where ancestry switches from one species to the other. In contrast to existing analyses of hybrid genomes, this approach will easily scale to entire genomes. Computer simulations will be used to quantify the effects of selection, migration and genetic drift on ancestry junctions across the genome. A range of genetic architectures of reproductive isolation will be investigated to determine the conditions under which selection against hybrids leaves detectable genomic signatures. This theoretical framework will be applied to new genomic data collected in hybrids between two subspecies of house mice that are excellent models for studying speciation in progress. Incompatible genomic regions responsible for reproductive barriers between new species will be identified.