Author: Karalyn Aronow

Publisher:

Published: 2011

Total Pages: 14

ISBN-13:

The aim of this project was to analyze relationships among populations of Crotalus adamanteus (Eastern Diamondback Rattlesnake) and to compare phylogeographic patterns across different classes of genes. The objective was to determine the effect of selective pressures on the detection of barriers to gene flow. For example, venom genes are under strong positive selection and allow an analysis of the rate of allele exchange in a gene that directly affects the fitness of an individual. This selection might drive alleles through phylogeographic barriers that limit the spread of neutral alleles. The relationship between nontoxin genes and fitness is not as clear and can be difficult to establish. However, most variation in these genes is neutral and determined by stochastic events. The type of selection on a gene will affect the phylogeographic pattern displayed. Prior phylogeographic studies have used either neutral markers (e.g., microsatellites) or genes not directly involved in specific adaptations (e.g., mitochondrial genes). One venom gene, two mitochondrial genes, one nuclear gene, and one pseudogene were compared for patterns of adaptation and the presence of geographic barriers to gene flow. This novel approach to studying gene flow could have an impact on defining taxonomic groups and conservation efforts, as well as serve as a guide for choosing appropriate genetic markers for other species. In the venom gene that was analyzed, it appeared the high level of selection led to alleles being driven across the barriers to gene flow of alleles under neutral selection.