On the evolutionary history and population genetic structure of the North American mountain goat (Oreamnos americanus)

• Mountain goat evolution

• Author / Creator

  Shafer, Aaron BA

• The spatiotemporal scale at which genetic diversity is assessed can provide insights into both broad- and fine-scale patterns in ecology and evolution. I examined the distribution of genetic diversity and the evolutionary history of the North American mountain goat (Oreamnos americanus). I first reviewed how the unique physiography and glacial history of northwestern North America shaped the regions’ genetic diversity. After reviewing more than 100 published studies, I found that species with high dispersal ability or with large contemporary ranges were the most likely to have resided in multiple refugia. Shifting to mountain goats, I reexamined the phylogenetic affinities of the mountain goat using a total evidence approach and likelihood-based tests of alternative hypotheses. I evaluated all published topologies and found mountain goats to be an independent basal lineage in the Caprinae family. I then examined the phylogeographic and population structure of the mountain goat using a variety of molecular markers. I found evidence of a hitherto unknown northern and coastal refugia, and found no association between immune gene variation and refugial history. The latter finding suggests that the current distribution of immune diversity was not a direct result of the last glacial maximum. Examining the spatial genetic structure of mountain goats, I detected seventeen highly differentiated subpopulations and found that mountain ranges facilitated gene flow. I then examined the fine-scale landscape genetic structure of mountain goats by combining genetic data with mountain goat location data using geographic information systems. I showed that summer habitat used by female mountain goats was the best predictor of gene flow, and identified a suite of habitat variables important for genetic connectivity. Finally, I found that dispersing mountain goats tended to be less genetically diverse than residents, which supports the fitness-associated dispersal hypothesis. These results shed important insight on the evolution and ecology of mountain goats and have implications for conserving the alpine and its inhabitants.

• Subjects / Keywords

  • Mountain goat
  • Refugia
  • Landscape genetics
  • Phylogeography

• Graduation date

  Spring 2012

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R37Q21

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.