Date of Award

1-1-2019

Document Type

Thesis

Degree Name

M.S.

Department

Biological Sciences

First Advisor

Robin M. Tinghitella, Ph.D.

Keywords

Divergent selection, Genetic divergence, Natural selection, Phenotypic divergence, Polymorphism, Sexual selection

Abstract

Recent research has led to a much better understanding of the evolutionary processes that mold and structure variation within and among populations. How populations diverge at the genome-wide level and how polymorphism is maintained within a species, however, remains unclear. We address these questions with two freshwater color morphs, red and black, of the threespine stickleback fish (Gasterosteus aculeatus) from the northwest United States, in which a shift from red to black nuptial coloration occurred in several locations following glacial retreat. We measured phenotypic variation in a suite of traits and used next generation sequencing to characterize within-species and among-morph genetic variation between the two morphs. We found substantial phenotypic and genetic divergence between color morphs, and patterns observed in a third, "mixed" morph that are likely due to hybridization between anadromous and freshwater stickleback. This work highlights the central role of natural and sexual selection in the evolution of divergence in nature.

Publication Statement

Copyright is held by the author. User is responsible for all copyright compliance.

Provenance

Received from ProQuest

Rights holder

Clara Sophie Jenck

File size

81 p.

File format

application/pdf

Language

en

Discipline

Ecology, Evolution & development

Included in

Genetics Commons

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