Dissertation
DESCRIBING HOW SELECTION, RECOMBINATION, AND THE ENVIRONMENT INFLUENCE THE EVOLUTIONARY GENETICS OF DIVERGING POPULATIONS OF THEOBROMA CACAO AND ANOPHELES GAMBIAE
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000005480
Handle:
https://hdl.handle.net/2376/119179
Abstract
Evolutionary genetics pertains to the identification of the genetic variants that exist within a species, especially those that contribute to evolutionary change. However, our understanding of the distribution of molecular adaptations and recombination landscapes are still limited to small geographic ranges, few sampled populations, and highly diverged species. Using full genome data from two different model systems, Theobroma cacao and Anopheles gambiae, we elucidated the distribution of molecular signatures of adaptation and the recombination landscape across a large geographic range, including multiple closely related populations. Specifically, we addressed three major questions: 1.) What does the distribution of molecular signatures of adaptation look like throughout the natural geographic range of Theobroma cacao? 2.) How does the recombination landscape vary across closely related populations of Anopheles and how does it impact levels of genetic diversity and divergence? 3.) What are the underlying genetic variants that contribute to local adaptation along the distribution of Anopheles? For the first question, we analyzed full genome data from ten populations of Theobroma cacao, genomic location of known disease resistance genes, and environmental data to elucidate the distribution of molecular signatures of adaptation. We found that most molecular signatures of adaptation were local in nature as they were only detected in a single population. For the second question we analyzed the genome of nine populations of Anopheles to compare recombination landscapes and quantify its impact of genetic diversity and divergence. We showed large variations in fine-scale recombination rates as well as significantly larger estimates of nucleotide diversity and divergence within recombination hotspots. Lastly, for the third question, we used full genome data from populations of Anopheles to further elucidate the underlining genetic variants that were associated to the surrounding environment. We identified thousands of genomic regions within and between inversions that were associated to precipitation and temperature gradients. Importantly, the results of my dissertation will offer significant insight towards improving our resolution on how we identify and infer the evolutionary genetics of a species and we encourage future studies to take a similar approach to the methods performed in this dissertation.
Metrics
3 File views/ downloads
24 Record Views
Details
- Title
- DESCRIBING HOW SELECTION, RECOMBINATION, AND THE ENVIRONMENT INFLUENCE THE EVOLUTIONARY GENETICS OF DIVERGING POPULATIONS OF THEOBROMA CACAO AND ANOPHELES GAMBIAE
- Creators
- Joel T Nelson
- Contributors
- Omar E. Cornejo (Advisor)Jeremiah W. Busch (Committee Member)Richard G. Gomulkiewicz (Committee Member)Paul H. Hohenlohe (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Biological Sciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 138
- Identifiers
- 99900592258701842
- Language
- English
- Resource Type
- Dissertation