Date of Degree
Access restricted until 08/31/2019
PhD (Doctor of Philosophy)
John M. Logsdon Jr.
First Committee Member
Second Committee Member
Third Committee Member
Fourth Committee Member
The fate of any lineage is contingent on the rate at which its genome changes over time. Genome dynamics are influenced by patterns of mutation and recombination. Mutations as the raw force of variation can be acted on independently during exchanges of homologous genetic regions via meiotic recombination. While molecular evolution in sexual lineages is impacted by both mutation and recombination, asexual lineage fate is primarily influenced by the mutation rate; recombination is often altered or absent in asexuals. Although multiple studies show accelerated mutation accumulation in asexual lineages that have lost recombination, virtually nothing is known about rate patterns when meiosis is retained. Here, I use parasitic wasps in genus Diachasma to investigate genome evolution in a recently-derived asexual lineage. I provide evidence that asexual Diachasma possess a canonical set of meiosis genes as well as high levels of genomic homozygosity. Taken together, these observations support an active, albeit modified, form of meiosis in this asexual lineage. In addition, I present the first documentation of accelerated mutation accumulation in the nuclear genome of a naturally-occurring, meiotically- reproducing organism. If harmful, these mutations could impede asexual lineage persistence and contribute strong support for the long-term benefits of sex.
asexual evolution, Diachasma, meiosis genes, mutation accumulation, recombination
xii, 284 pages
Includes bibliographical references (pages 281-284).
Copyright © 2018 Eric S. Tvedte
Tvedte, Eric S.. "Genome evolution in parasitic wasps: comparisons of sexual and asexual species." PhD (Doctor of Philosophy) thesis, University of Iowa, 2018.
Available for download on Saturday, August 31, 2019