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.
