Dissertation Research: Studies of Diversification in Anolis marmoratus Lizards

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Lizards of the genus Anolis are the most common and diverse terrestrial vertebrates in the Caribbean. Despite extensive knowledge about their ecology, behavior, and geographical distributions, little is known about levels of genetic variability within and between populations of the many species, and of how these levels affect processes of speciation. The morphologically diverse species Anolis marmoratus, with 12 named subspecies in the Guadeloupean archipelago of the Lesser Antilles, provides a test case for exploring the relationship between mating systems, levels of genetic variability, and speciation involving morphological change. Variation in this species is particularly conspicuous in color and pattern of adult males; characters that, along with signalling behavior, are important in social competition and mate recognition. Variation in these characters, leading to what is called assortative (that is, preferential) mating, will promote the accumulation of genetic differences among populations, a postulated first step leading to speciation (complete reproductive isolation). Faculty advisers David Wake and Harry Greene will supervise graduate student Christopher Schneider in a study of genetic, behavioral, and morphological variation in this group of anolis lizards. Emphasis is placed on nucleotide sequencing of select mitochondrial genes to acquire fine-scale evidence of variation and of gene flow between populations, within islands and between islands. The gene data will allow several tests of hypotheses concerning how male color patterns and display behaviors affect mating success, and thereby help structure local populations genetically. In turn, knowledge about the genetic structure of local populations will help test ideas about speciation processes in this diverse group of lizards.