Honors Program


Date of this Version

Summer 7-7-2022

Document Type



Alder, Peyton. 2022. Selfish Genes: Meiotic Drivers and Suppressors in Drosophila. Undergraduate Honors Thesis. University of Nebraska-Lincoln


Copyright Peyton Alder 2022.


Non-Mendelian segregation, also known as meiotic drive, is a phenomenon that causes distorted sex ratios in certain species when the driver is located on a sex chromosome. In the Drosophila simulans genome, two meiotic drivers, Dox (Distorter on X) and MDox (Mother of Dox) have been identified as well as two autosomal suppressors that work to keep them check, tmy (too much yin) and nmy (not much yang). Experiments utilizing fertility tests and molecular work were performed to understand more about the molecular mechanisms by which these genetic elements drive. Through a series of crosses using compound D. simulans sex chromosomes, a Drosophila mauritania Y-chromosome (Ymau) was crossed into the D. simulans wXD1 genotype to investigate the effects of Y chromosomal variation on the strength of sex-ratio distortion. In the second set of crosses, a loss-of-function allele at Ago2 (argonaute-2) was used to investigate the effects of loss of the RNAi pathway on sex-ratio distortion. The results showed that the Ymau chromosome is more resistant than the Ysim chromosome to the meiotic drivers Dox and MDox. Ago2 is essential for tmy and nmy and loss of function resulted in total sterility of all males. The sequence differences in the chromosomes explain why some are more vulnerable to Dox and MDox and why varying fertility phenotypes are seen between the different X-chromosomes.