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

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

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.