Sex-ratio meiotic drive is found in diverse groups of metazoans including arthropods, mammals and plants. Drive occurs because a selfish sex chromosome, usually the X chromosome, is able to debilitate the opposite sex chromosome. The result is that males carrying the driving X chromosome produce almost all daughters. Understanding the genetics of sex-ratio meiotic drive has been hindered by the association of drive loci with large inversions. The Drosophila affinis sex-ratio system has an additional level o complexity: males lacking a Y chromosome are fertile. In fact, a male with a driving X chromosome and no Y produces mostly sons - the driving X appears to be suicidal in the absence of a Y chromosome. I propose a strategy using next generation sequencing for genomic analysis of sex-ratio meiotic drive in Drosophila affinis. Using a combination of comparative genomics of the driving and non-driving X chromosomes and transcriptomic analysis of both chromosomes in males testes, I hope to identify candidate genes involved in the drive phenotype. Subsequent analysis will help identify specific genes. The approach is novel in that I will be attempting to map genes within inversions in a non-model species, and the methods I develop will facilitate similar analysis in other systems. The biological insight obtaine from our analysis may shed light on the genetics of sex-ratio meiotic drive and sex chromosome evolution, both of which have implications for fertility.
Drosophila melanogaster has long been used as a model for understanding a wide range of biological principles ranging from metabolism to disease to aging. Branching out to related Drosophila species allows for the exploration of equally important questions, specific to a particular species'biology. Understanding the genomics of sex-ratio meiotic drive and sex chromosome evolution may help us understand the basis of fertility problems in humans (reviewed in Burt and Trivers 2006).
|Unckless, R L; Clark, A G (2014) Sex-ratio meiotic drive and interspecific competition. J Evol Biol 27:1513-21|
|Orr, H Allen; Unckless, Robert L (2014) The population genetics of evolutionary rescue. PLoS Genet 10:e1004551|