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Graduation Term
Summer 2026
Degree Name
Master of Science (MS)
Department
School of Biological Sciences
Committee Chair
Pirmin Nietlisbach
Committee Member
Javier delBarco-Trillo
Committee Member
Thomas Hammond
Committee Member
Kara Andres
Abstract
Rising sea levels breaking up once-large coastal areas, along with the conversion of wildlands for anthropogenic use leads to decreased habitat available to wildlife, and what is left can be highly fragmented. Small, isolated populations are at an increased risk of extinction not only because of further habitat loss, but from genetic diversity being lost through the process of genetic drift, and the long-term genetic effects of habitat fragmentation remain unclear. Island populations are great natural systems to study the effects of long-term isolation on populations. Using North American deer mouse (Peromyscus maniculatus) populations in British Columbia, Canada’s Gulf Islands, I looked at how mutation frequencies of differently deleterious alleles are affected by both isolation and population size. We live-trapped deer mice on eight Southern Gulf Islands, two locations on Vancouver Island, and at two locations on the Canadian mainland. Outer-ear tissue was collected for DNA extraction and sequencing. Samples were sequenced at low depth (2x, n=160) and high depth (20x, n=10). SnpEff was used to determine the frequencies of differently deleterious alleles (HIGH, MODERATE, LOW, and MODIFIER). We found that while allele frequency did change with island size (used as a proxy for population size), there is no evidence that highly deleterious alleles change differently with island size than the less deleterious alleles in the MODERATE, LOW, and MODIFIER categories. Small and isolated populations are at higher risk of extinction than larger and less isolated ones, therefore genetic management strategies should focus on restoring and maintaining gene flow.
Access Type
Thesis-ISU Access Only
Recommended Citation
Koeplin, Madeline S., "Of mice and mutations: Frequencies of differently deleterious alleles in small, highly isolated populations of North American deer mice (Peromyscus maniculatus)" (2026). Theses and Dissertations. 2402.
https://ir.library.illinoisstate.edu/etd/2402