Date of Award
Fall 12-2013
Degree Type
Dissertation
Degree Name
Ph.D.
Degree Program
Conservation Biology
Department
Biological Sciences
Major Professor
Dr. Steven G. Johnson
Second Advisor
Dr. C. Darrin Hulsey
Third Advisor
Dr. Jerome J. Howard
Fourth Advisor
Dr. Charles D. Bell
Fifth Advisor
Dr. Simon Lailvaux
Abstract
Phylogeography aims to understand the processes that underlie the distribution of genetic variation within and among closely related species. Although the means by which this goal might be achieved differ considerably from those that spawned the field some thirty years ago, the foundation and conceptual breakthroughs made by Avise are nonetheless the same and are as relevant today as they were two decades ago. Namely, patterns of neutral genetic variation among individuals carry the signature of a species’ demographic past, and the spatial and temporal environmental heterogeneity across a species’ geographic range can influence patterns of evolutionary change. Aquatic systems throughout Mexico provide unique opportunities to study phenotypic plasticity and evolution in relation to climatic and environmental selective forces. There are several unique, often isolated aquatic environments throughout Mexico that have a history of geographic isolation and reconnection. The first study presented herein shows significant mitochondrial sequence divergence was also discovered between L. megalotis populations on either side of the Sierra de San Marcos that bisects the valley of Cuatro Ciénegas and that the populations in the valley are genetically distinct from those found outside of the valley. The second study recovered signals of two divergence events in Cuatro Ciénegas for six codistributed taxa, and reveals that both events occured in the Pleistocene during periods of increased aridity suggesting that climatic effects might have played a role in these species’ divergence. The final study presents an Illumina-based high-resolution species phylogeny for Astyanax mexicanus providing added support that there are multiple origins to cave populations and further clarifying the uniqueness of the Sabinos and Rio Subterráneo caves.
Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.
Recommended Citation
Coghill, Lyndon M., "Statistical and Comparative Phylogeography of Mexican Freshwater Taxa in Extreme Aquatic Environments" (2013). University of New Orleans Theses and Dissertations. 1724.
https://scholarworks.uno.edu/td/1724
Included in
Biodiversity Commons, Bioinformatics Commons, Biology Commons, Evolution Commons, Other Ecology and Evolutionary Biology Commons, Terrestrial and Aquatic Ecology Commons
Rights
The University of New Orleans and its agents retain the non-exclusive license to archive and make accessible this dissertation or thesis in whole or in part in all forms of media, now or hereafter known. The author retains all other ownership rights to the copyright of the thesis or dissertation.