Graduation Year

2015

Graduation Month

May

Document Type

Thesis

Degree Name

Bachelor of Arts

School or Department

Biological Sciences, Division of

Faculty Mentor Department

Biological Sciences, Division of

Faculty Mentor

Jeffrey Good

Abstract

Speciation is the biological process by which new species arise. Hybridization occurs in nature when two distinct lineages produce hybrid offspring and exchange genes. Understanding these events is key to understanding the process of evolution and the origin of biodiversity. Western chipmunks are an example of a widely distributed group with possible hybridization and gene flow between presently diverging species. Past studies examining this system suggest that there has been some hybridization and gene flow during the recent, rapid radiation of western chipmunk species. However, the overall importance and frequency of hybridization between chipmunk species remains unclear. Previously, the evolutionary relationships within the chipmunk group have been reconstructed using sequences from mitochondrial DNA and four nuclear genes. The full resolution of the chipmunk phylogeny rests on additional sequencing of DNA to provide a more complete picture of the relationships between the species, and the frequency and extent of hybridization. This project begins to address this by generating genome-wide sequencing data using samples from 40 chipmunks of 15 species and various localities. DNA extracts from each sample were prepared for next-generation genetic sequencing. A custom exon capture experiment was then used to target nine million base pairs of the chipmunk genome for Illumina sequencing. These sequencing efforts generated data spanning thousands of genes in all 40 samples, which was used to construct an overall phylogeny for the group. These data provide the foundation for ongoing studies to resolve the chipmunk phylogeny and the history for hybridization in this system.

Honors College Research Project

1

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© Copyright 2015 Erin Nordquist