Selection Footprints and Mapping

The research funded by this grant explores a relatively new approach to gene mapping. The selection (or hitchhiking) mapping approach exploits the fact that genetic diversity will be reduced near a gene under strong selection, due to statistical associations that develop along a chromosome. The recent increase in availability of genetic diversity data, due to technical improvements and reductions in cost of genome-wide sequencing, have made such techniques feasible. So far, this approach has primarily been applied to human data sets, with the goal of understanding the selective processes that have acted on the human genome over the course of evolution. An important issue is that while there has been a large effort applied to data generation and analysis (including the publication of some controversial conclusions regarding human evolution), the power and limitations of this approach have not been seriously addressed by researchers. The importance of our work is that it focuses on genes for which there is strong historical evidence of selection, allowing us to characterize the diversity patterns generated by selection. In most wild species and humans, this would not be possible since it is rare that a gene or genetic region is definitely known to have been under selection. However, in domesticated species, where the selection pressure has been strong and often on well-defined traits, there are more opportunities for implementation of this approach to identify genes related to the domestication process. This research has examined the diversity patterns at neutral markers in the region of three cattle genes with strong evidence of selection as well as for simulated genotypic data, generated under specific selection regimes.