Ecological and Evolutionary Genomics: Differential Variability of Gene Expression and Fine-Scale Adaptive Divergence Among Microhabitats of Large Fundulus heteroclitus Populations

Wagner, Dominique N. (2017) Ecological and Evolutionary Genomics: Differential Variability of Gene Expression and Fine-Scale Adaptive Divergence Among Microhabitats of Large Fundulus heteroclitus Populations. PhD thesis, University of Miami.

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Abstract

Adaptive evolution on ecological timescales shapes communities. However, adaptation among environments relies on isolation or large selection coefficients that exceed migration effects. This reliance is tempered if adaptation from standing genetic variation is polygenic – does not depend on one allele completely replacing another but instead requires small allele frequency changes at many loci. Thus, whether individuals can evolve adaptation to fine-scale habitat variation is not resolved. To investigate this process, the gene expression and genetic divergence of a teleost fish, Fundulus heteroclitus, was explored. Among nearby (< 200m) microhabitats in three separate saltmarshes, and over the course of a season (spring to fall), thousands of single-nucleotide polymorphisms (SNPs) were analyzed. Among these SNPs, 1.3-2.3% have large and highly significant differences among microhabitats (mean FST = 0.15; false discovery rate (FDR) ≤ 1%), and 1.8-5.7% are significantly different between seasons (mean FST = 0.077 to 0.597; FDR ≤ 1%). The divergence among microhabitats and between seasons for these SNPs is larger than that among populations, exceeds neutral expectation, and indicates surprising population structure among microhabitats. These data suggest that polygenic selection is surprisingly effective in altering allele frequencies over very small geographic distances.

Item Type: Thesis (PhD)
Additional Information: It has been accepted for inclusion in Open Access Dissertations by an authorized administrator of Scholarly Repository. For more information, please contact
Subjects: G Geography. Anthropology. Recreation > GF Human ecology. Anthropogeography
Q Science > QH Natural history > QH301 Biology
Divisions: Comparative
Depositing User: Emmanuel Ndorimana
Date Deposited: 11 Jun 2018 13:10
Last Modified: 11 Jun 2018 13:10
URI: http://thesisbank.jhia.ac.ke/id/eprint/4740

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