Genomic Analysis of Chronic Heat Stress Resistance in the Nematode Caenorhabditis remanei
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Date
2017
Authors
Claridge, Sally Elizabeth
Journal Title
Journal ISSN
Volume Title
Publisher
University of Oregon
Abstract
Selection can drive sub-populations to diverge from each other, but gene flow can homogenize them. Migration-selection dynamics are one of the fundamental aspects of speciation and population divergence, but they have not been rigorously investigated in an experimental context. We aimed to elucidate how gene flow affects the rate of adaptation to a novel environment via the experimental evolution of the nematode Caenorhabditis remanei in a chronic heat stress environment. Five replicate populations of C. remanei were evolved to novel (31 ̊C) and ancestral (20 ̊C) environments and treated with 0- and 5-percent migration rates. Female fecundity information was collected to estimate the extent of adaptation in the heat-stress-evolved population. The migration treatment stunted the rate of adaptation to the novel environment, though population divergence still occurred. We anticipate there will be genomic changes in the descendant lines that lead to adaptation. Whole genome sequencing data from both the ancestral and descendant populations will be compared on a locus-by-locus basis to identify these changes. Migration is expected to reduce signatures of differentiation from weakly selected loci and to enhance signatures associated with loci of large effect.
Description
52 pages. A thesis presented to the Department of Biology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2017
Keywords
Biology, Experimental evolution, Caenorhabditis Remanei, Stress resistance, Selection, Gene flow