Document Type


Date of Degree

Summer 2018

Access Restrictions

Access restricted until 08/31/2019

Degree Name

PhD (Doctor of Philosophy)

Degree In


First Advisor

Logsdon, John M., Jr.

Second Advisor

Forbes, Andrew

First Committee Member

Neiman, Maurine

Second Committee Member

McAllister, Bryant

Third Committee Member

Scheetz, Todd

Fourth Committee Member

Kitchen, Andrew


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

Available for download on Saturday, August 31, 2019

Included in

Biology Commons