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dc.contributor.advisorCannatella, David C.en
dc.creatorGuarnizo, Carlos Enriqueen
dc.date.accessioned2011-10-20T20:45:30Zen
dc.date.available2011-10-20T20:45:30Zen
dc.date.issued2011-08en
dc.date.submittedAugust 2011en
dc.identifier.urihttp://hdl.handle.net/2152/ETD-UT-2011-08-3726en
dc.descriptiontexten
dc.description.abstractComplex interactions between topographic heterogeneity and steep gradients in climate and environmental conditions are commonly assumed to promote biotic diversification. Using tropical frogs as a model, I investigate the nature of these interactions that disrupt migration between populations, causing genetic divergence and speciation. I determine the role of several putative factors that affect gene flow (Euclidean distances, Least Cost Path (LCP) distances, topographic complexity, and elevation difference) and promote genetic structure (FST) between populations of three tropical Andean frog species. Moreover, I investigate, from an intraspecific perspective, whether montane frog species display on average larger genetic distances per kilometer relative to lowland species. Finally, I test if recent genetic divergence caused by topographic barriers to gene flow is paralleled by independent character systems such as acoustics and morphological traits in the high Andean frog Dendropsophus labialis. Even though the effect of geographic features on migration (and conversely, FST) was species-specific, LCP and Euclidean distances had the strongest effect on migration rate. Topographic complexity also reduced migration rate whereas elevation difference did not have an effect. I found that indeed highland species show larger genetic distances per kilometer between haplotypes than do lowland species. Also, genetic divergence is strongly associated with topographic heterogeneity, which is an intrinsic characteristic of montane regions. Finally, I found that acoustic variation in D. labialis diverges according to genealogical history, but external morphology does not follow this relationship. Stochastic processes due to genetic drift appear to be a better explanatory mechanism for the divergence in calls than adaptive variation. The strong and congruent divergence observed in acoustic and genetic characters indicates that these two groups correspond to morphologically cryptic parapatric species. Overall, the results of this study suggest some of the mechanisms that allow tropical mountains to promote intraspecific genetic divergence. The combined effect of ridges (promoting allopatric differentiation) and environmental gradients across elevation (promoting parapatric differentiation) are effective forces that are present mostly in highland biomes. Unfortunately, such biomes are critically threatened by habitat destruction and climate change, possibly more than any other biome on earth.en
dc.format.mimetypeapplication/pdfen
dc.language.isoengen
dc.subjectBiogeographyen
dc.subjectAndean frogsen
dc.subjectMountainsen
dc.subjectLowlandsen
dc.subjectGenetic structureen
dc.subjectTropicsen
dc.subjectElevation gradientsen
dc.subjectVicarianceen
dc.subjectIsolation by distanceen
dc.titleEffect of topography on genetic divergence and phenotypic traits in tropical frogsen
dc.date.updated2011-10-20T20:46:04Zen
dc.identifier.slug2152/ETD-UT-2011-08-3726en
dc.contributor.committeeMemberBull, James J.en
dc.contributor.committeeMemberJuenger, Thomasen
dc.contributor.committeeMemberWilke, Clausen
dc.contributor.committeeMemberPerez, Franciscoen
dc.description.departmentEcology, Evolution and Behavioren
dc.type.genrethesisen
thesis.degree.departmentEcology, Evolution and Behavioren
thesis.degree.disciplineEcology Evolution, and Behavioren
thesis.degree.grantorUniversity of Texas at Austinen
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophyen


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