Fitness and transmission of a selfish X chromosome in female Drosophila testacea
| dc.contributor.author | Powell, Candice | |
| dc.contributor.supervisor | Perlman, Steven John | |
| dc.date.accessioned | 2021-05-27T00:25:05Z | |
| dc.date.copyright | 2021 | en_US |
| dc.date.issued | 2021-05-26 | |
| dc.degree.department | Department of Biology | |
| dc.degree.level | Master of Science M.Sc. | en_US |
| dc.description.abstract | Selfish genetic elements break the rules of Mendelian inheritance to bias their transmission to following generations, often with negative fitness consequences. A striking example involves selfish X chromosomes that operate in males and interfere with the production of sperm that carry a Y chromosome. Only X chromosome-bearing sperm are produced, and this can result in extraordinary female-biased sex-ratio distortions. Most studies have focused on how selfish X chromosomes operate in and affect males, and there has been relatively little work on their consequences in females. In this thesis, I characterize fitness effects and transmission in females, in a recently discovered selfish X chromosome system in Drosophila testacea, a common woodland fly. I show that females with two copies of the selfish X chromosome have reduced fitness compared to females carrying zero, or one copy. Specifically, these females have a lower hatch rate and lifetime fecundity. Additionally, I show that heterozygous females are more likely to transmit the selfish X chromosome than the wildtype copy to their offspring. I observe this transmission bias in eggs, larvae, and adults, which suggests that the selfish X chromosome is preferentially segregating into the egg, rather than the polar bodies, during oogenesis. We believe this is the first documented case of a selfish X chromosome acting through both sexes. The negative fitness effects and the biased transmission in males and females will have important consequences on the evolutionary dynamics of the selfish X chromosome. In addition, the phenomenon of biased transmission in both sexes has the potential to yield interesting insights in the mechanism of meiotic drive. | en_US |
| dc.description.scholarlevel | Graduate | en_US |
| dc.identifier.uri | http://hdl.handle.net/1828/12998 | |
| dc.language | English | eng |
| dc.language.iso | en | en_US |
| dc.rights | Available to the World Wide Web | en_US |
| dc.subject | drosophila testacea | en_US |
| dc.subject | selfish genetic element | en_US |
| dc.subject | meiotic drive | en_US |
| dc.subject | centromere drive | en_US |
| dc.title | Fitness and transmission of a selfish X chromosome in female Drosophila testacea | en_US |
| dc.type | Thesis | en_US |