Volker Bahn (Committee Member), Scott Baird (Committee Member), Jeffrey Peters (Advisor)
Master of Science (MS)
The Pleistocene was characterized by fluctuations in climate causing repeated advances and retreats of glacial ice. The advancing ice sheets caused habitat fragmentation which initiated population divergence and speciation events between eastern and western avian populations within northern temperate forests. Based on mitochondrial DNA (mtDNA) control region sequences, North American Wood Duck (Aix sponsa) populations fit this model of divergence. However, mtDNA is maternally inherited, and thus may not reflect the genomic history of this species, because of male biased-dispersal, selection, or stochastic lineage sorting. To test the "Late Pleistocene divergence" hypothesis, I sequenced 11 independent nuclear introns (nuDNA) for 45 individuals sampled from eastern and western populations of Wood Ducks. Although two loci were significantly structured between East and West, overall population structure was considerably weaker for nuDNA (mean FST = 0.027; range = 0.0 to 0.131) than for mtDNA (FST = 0.31). Furthermore, genetic assignment tests and mark-recovery data were both consistent with male-biased dispersal between regions. Despite the influence of male-biased dispersal, estimates of time since divergence from both nuDNA and mtDNA were consistent with the last glacial advance splitting the two populations, thus supporting the Late Pleistocene divergence hypothesis. This study illustrates the utility of using nuDNA to test hypotheses derived from mtDNA analyses, which strengthens inferences of population history.
Department or Program
Department of Biological Sciences
Year Degree Awarded
Copyright 2011, all rights reserved. This open access ETD is published by Wright State University and OhioLINK.