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The evolutionary genetics of recombination and segregation in Drosophila

URL to cite or link to: http://hdl.handle.net/1802/34305

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PDF of thesis.
Thesis (Ph. D.)--University of Rochester. Department of Biology, 2018.
During meiosis, sexually reproducing eukaryotes exchange genetic material via recombination and segregate homologous chromosomes into gametes. Surprisingly, some genes involved in meiotic recombination and chromosomal segregation experience frequent evolutionary turnover. Growing evidence suggests selfish genetic elements— DNA entities that promote their own transmission at the expense of other genes in the genome— are a significant evolutionary force driving rapid molecular evolution at genes involved in an otherwise conserved biological process. The research in this dissertation integrates classical, molecular, and population genetics to study the evolution of recombination rates and biased chromosomal segregation in Drosophila. First, in Chapters 2-4, I focus on the evolution of recombination rates in Drosophila. In Chapter 2, I perform an evolutionary screen to identify a meiosis gene with a history of recurrent positive selection that might contribute to differences in the rate of crossing over between two closely related Drosophila species. I then use a transgenic approach to show this gene, mei-217/mei-218, mediates the species differences in the rate and patterning of crossing over. In Chapter 3, I use further transgenic analyses to functionally dissect mei-217/mei-218 to determine which gene regions control the species differences in crossing over. In Chapter 4, I explore the long-term molecular evolution of mei-217/mei-218 and find evidence for frequent positive selection during the phylogenetic history of Drosophila. I find that mei-217/mei-218 wildtype alleles of two additional Drosophila species have also functionally diverged in their control of crossing over. I speculate that recurrent bouts of adaptive functional evolution at mei-217/-218 might reflect a history of coevolution with selfish genetic elements. Next, in Chapter 5, I turn to the evolution of a meiotic drive system, Segregation Distorter, that causes biased segregation in Drosophila melanogaster. I use molecular and population genetic tools to investigate the age, geographic origins, and population dynamics of Segregation Distorter chromosomes. I find that despite its stable frequency, Segregation Distorter chromosomes experience frequent selective sweeps and replacement events.
Contributor(s):
Cara L. Brand - Author

Daven C. Presgraves - Thesis Advisor

Primary Item Type:
Thesis
Identifiers:
Local Call No. AS38.669
Language:
English
Subject Keywords:
Drosophila; Evolution; Meiosis; Meiotic Drive; Recombination; Selfish Genetic Elements
Sponsor - Description:
National Institutes of Health (NIH) -
Alfred P. Sloan Foundation -
David & Lucile Packard Foundation -
National Science Foundation (NSF) - DDIG
First presented to the public:
10/5/2019
Originally created:
2018
Date will be made available to public:
2019-10-05   
Original Publication Date:
2018
Previously Published By:
University of Rochester
Place Of Publication:
Rochester, N.Y.
Citation:
Extents:
Illustrations - illustrations (some color)
Number of Pages - xvi, 123 pages
License Grantor / Date Granted:
Catherine Barber / 2018-10-18 06:43:49.531 ( View License )
Date Deposited
2018-10-18 06:43:49.531
Date Last Updated
2018-10-18 13:33:12.757
Submitter:
Catherine Barber

Copyright © This item is protected by copyright, with all rights reserved.

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