Sponsor
Portland State University. Department of Biology
First Advisor
Suzanne Estes
Term of Graduation
Spring 2025
Date of Publication
6-9-2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy (Ph.D.) in Biology
Department
Biology
Language
English
Subjects
C. elegans, mitochondrial evolution, mitonuclear
Physical Description
1 online resource (vii, 227 pages)
Abstract
My dissertation explores the complex interactions between mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) and aims to reveal how mitochondrial genomes coevolve in response to states of mitonuclear dysfunction utilizing experimental evolution studies with Caenorhabditis elegans nematodes. First, I review the current state of C. elegans and other studies that have explored mitonuclear interactions and highlight how Caenorhabditis are excellent model systems for studying these interactions. Here I identify gaps in current knowledge and propose future research questions. Second, I expand upon my co-authored publication, Bever et al. (2022), that provided an incomplete test for the mitonuclear sex hypothesis and explored the impacts of mitochondrial electron transport chain (ETC) dysfunction and different mating systems on fitness evolution within a single ETC mutant strain. I sought to answer whether and to what extent populations experiencing different types of mitonuclear dysfunction can recover fitness after evolving in large populations sizes across 60 generations. In alignment with theory, I found that the amount of recovery depended on ancestral starting fitness--which was conflated with the effects of ETC genomic location. I also found no correlation between mtDNA copy number and evolved fitness. Third, I investigated the mitochondrial genomic signatures of evolution that occurred in response to the mitonuclear mismatch and ETC dysfunction. Here I identified 116 mtDNA variants that arose during the 60 generations of laboratory evolution and analyzed their locations, mutational spectra, and potential impacts of the alternative proteome. Chapter 5 synthesizes my findings and outlines fruitful avenues of future study.
Rights
© 2025 Zachary Paul Dietz
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Persistent Identifier
https://archives.pdx.edu/ds/psu/43789
Recommended Citation
Dietz, Zachary Paul, "Sex and the Genetic Architecture of Mitonuclear Evolution" (2025). Dissertations and Theses. Paper 6818.