Humboldt State University



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dc.contributor.advisor Jennings, W. Bryan en Gottscho, Andrew en 2010-04-02T21:52:20Z en 2010-04-02T21:52:20Z en 2010-03 en
dc.identifier.uri en
dc.description Thesis (M.A.)--Humboldt State University, Biological Sciences, 2010 en
dc.description.abstract Analyzing DNA sequence data from multiple unlinked nuclear loci in a coalescent Isolation-with-Migration (IM) model is a statistically powerful method for estimating population divergence times, effective population sizes, and gene flow. This approach was used to reconstruct the evolutionary history of the Mojave fringe-toed Lizard, Uma scoparia, which is restricted to windblown sand habitats in the Mojave and Colorado Deserts of southern California and western Arizona, a region that is thought to have undergone dramatic climatic change during and since the Pleistocene epoch. To shed light on the origin of this species, I analyzed 15 nuclear loci (621,694 total bp) representing twenty localities of U. scoparia and four localities from its sister species to the south, U. notata. I found a latitudinal gradient in heterozygous SNPs and indels, low nucleotide diversity in U. scoparia (π = 0.148%, SD = 0.167%), particularly relative to U. notata (π = 0.469%, SD = 0.366%), and reciprocal monophyly in 3/15 gene trees. Using the IM model, I estimated with 95% confidence that U. scoparia and U. notata speciated in the Pleistocene epoch (~1 – 1.4 mya, 95% CI ~0.7 mya – 2.1 mya) without significant gene flow (2Nm < 1), an estimate that is robust to violations of the no-recombination assumption. I also found that U. notata has 2-5 times the effective population size of U. scoparia. These findings suggest that U. scoparia originated in the Pleistocene epoch and was confined to a Colorado Desert refuge during glacial maxima; northern populations represent a recent range expansion. en
dc.description.sponsorship Fort Irwin National Training Center, Community Foundation, Joshua Tree National Park Association, Bureau of Land Management Needles Field Office, Judith and Alistair McCrone, Humboldt State University Biological Sciences Department en
dc.language.iso en_US en
dc.publisher Humboldt State University en
dc.subject Lizard en
dc.subject Speciation en
dc.subject Gene flow en
dc.subject Pleistocene en
dc.subject Mojave Desert en
dc.subject Colorado Desert en
dc.subject Uma en
dc.subject Coalescent en
dc.subject Multi-locus en
dc.subject Biogeography en
dc.subject Low genetic diversity en
dc.title Coalescent analysis of fifteen nuclear loci reveals Pleistocene speciation and low genetic diversity in the Mojave Fringe-toed Lizard, Uma scoparia en
dc.type Thesis en
dc.description.program Biology en

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