Unrestricted.2016-11-152013-08-272016-11-152013-05http://hdl.handle.net/2346/50326The primary objective of this study was to apply a multifaceted approach to understand the historical and contemporary aspects of hybridization between 2 species of ground squirrels (Ictidomys). Genetic and ecological data were used to determine the influence of historical biogeography on hybridization, the extent of contemporary hybridization, and the role the environment plays in determining locations of contact and potential hybridization. In Chapter I, the subject of hybridization and hybrid zones and its part in the speciation process was introduced. In addition, literature relevant to hybridization in mammals was discussed. Relevant to this dissertation, hybridization between the Rio Grande ground squirrel (I. parvidens) and the thirteen-lined ground squirrel (I. tridecemlineatus) was examined. In Chapter II, the historical contribution to hybridization between I. parvidens and I. tridecemlineatus was evaluated. Given the genetic data incorporated in this study, these species likely have undergone an ancient hybridization event, leading to mitochondrial capture in areas of previous sympatry. In Chapter III, the extent of hybridization at areas previously identified to have such was determined. By combining sequence data used in Chapter II with a genome-wide scan, hybridization was limited to small populations, with hybrids in a mosaic spatial pattern. In Chapter IV, the contributions of climate and anthropogenic changes to habitat were assessed. Through ecological niche modeling, it was determined that climate contributed the most to distributional patterns of both species. However, recent habitat modifications might have had an additive effect on both species’ distributions. Concluding remarks are provided in Chapter V.application/pdfen-USAmplified fragment length polymorphismClimate changeCytochrome b (Cyt-b)Ecological niche modelingHabitat modificationHybridizationIctidomysMitochondrial captureMosaic hybrid zonePleistoceneSecondary contactSmcY (antibody)Dissertation