Dissertations and Theses @ UNI

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Thesis (UNI Access Only)

Keywords

Rainbow darter--Genetics; Rainbow darter--Habitat;

Abstract

Historic cycles of glacial advance and retreat throughout the Pleistocene Epoch helped shape the contemporary landscape features of the North American continent. These recurrent glacial events greatly affected local climates, disturbed aquatic habitats, and altered the distribution of freshwater species. The repeated disturbances are expected to leave a persisting influence on the genetic structure of local populations, preventing adherence to a pattern of directional hierarchy known as the stream hierarchy model. In this study, genome-wide single nucleotide polymorphisms (SNPs) were utilized to identify the present-day population connectivity and genetic structure of the Rainbow Darter (Etheostoma caeruleum) in river networks with disparate glacial histories. The generation of SNP datasets through restriction site-associated DNA sequencing (RADseq) was explicitly conducted to resolve fine-scale genetic structure. The river systems selected for this study were the Volga River in the previously glaciated upper Mississippi River basin and the Meramec River of the historically unglaciated Ozark Plateau. Rainbow Darters were sampled from five localities within each of these rivers at distances dictated by organismal life history and habitat preferences. A series of bioinformatic analyses were performed on three datasets: one for the total combined localities of both rivers and one for each of the rivers independently. The results obtained from these datasets supported a lasting influence of historic glaciation on the population genetic structure of affected Rainbow Darter populations. The populations within the unglaciated Meramec River adhered to the stream hierarchy model, with a directional hierarchy based on the life history and preferences of the species. Populations in the Volga River did not exhibit such structure but indicate repeated colonization and extirpation due to cyclic glaciation. These outcomes demonstrate the applicability of SNP data to infer fine-scale genetic structure and a necessity to consider the geological and climatological history of habitat when interpreting these results.

Year of Submission

2021

Degree Name

Master of Science

Department

Department of Biology

First Advisor

Peter Berendzen, Chair, Thesis Committee

Date Original

2021

Object Description

1 PDF file (vii, 43 pages)

Language

en

File Format

application/pdf

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