Sex chromosome meiotic drive is caused by a selfish genetic element that produces a highly skewed offspring sex ratio, often by killing all Y-bearing spermatids during spermatogenesis. This process results in intense intragenomic conflict between the selfish meiotic drive element and the rest of the genome, which is expected to have far reaching effects on the evolution of the genome. The long-term goal of this proposal is to better understand how meiotic drive evolves.
One aim utilizes RNA-seq to sequence the testes transcriptome of drive and non-drive males from five wild populations of the stalk-eyed fly, Teleopsis dalmanni, in order to identify genes associated with meiotic drive in these populations. These data will be used to test the hypothesis that intragenomic conflict caused by meiotic drive has driven increased gene duplication and gene movement.
A second aim asks what selective forces affect the evolution of meiotic drive in populations. This question is addressed using an experimental evolution approach to ask whether sexual selection acts to limit the transmission of drive and how the presence of drive affects the evolution of sexually selected traits in artificial populations. This research expands our understanding of the evolution of meiotic drive by providing a useful contrast with previous research within the genus Drosophila, where sex ratio meiotic drive has also been studied. This proposal also has biomedical relevance because it will improve our understanding of spermatogenesis by investigating the evolution of natural variation in spermatogenesis, by comparing sex-ratio and standard males, on the level of genes and populations.
Sex chromosome meiotic drive causes an individual carrying the meiotic drive gene to have offspring of only one sex. This trait appears to have such negative consequences to the fitness of the carrier that we find ourselves asking, how did this trait evolve and how can it be maintained in a successful population? This proposal addresses questions about the evolution of sex chromosome meiotic drive in stalk-eyed flies by asking how evolutionary forces affect the frequency of the meiotic drive phenotype and how the genes underlying meiotic drive affect the evolution of populations.
|Paczolt, Kimberly A; Passow, Courtney N; Delclos, Pablo J et al. (2015) Multiple mating and reproductive skew in parental and introgressed females of the live-bearing fish Xiphophorus birchmanni. J Hered 106:57-66|