Transcriptome Differences between Alternative Sex Determining Genotypes in the House Fly, Musca domestica
Study Type:
Transcriptome Analysis
Abstract: Sex determination evolves rapidly, often because of turnover of the genes at the top of the pathway. The house fly, Musca domestica, has a multifactorial sex determination system, allowing us to identify the selective forces responsible for the evolutionary turnover of sex determination in action. There is a male determining factor, M, on the Y chromosome (Y^M), which is probably the ancestral state. An M factor on the third chromosome (III^M) has reached high frequencies in multiple populations across the world, but the evolutionary forces responsible for the invasion of III^M are not resolved. To test if the III^M chromosome invaded because of sex-specific selection pressures, we used mRNA sequencing to determine if isogenic males that differ only in the presence of the Y^M or III^M chromosome have different gene expression profiles. We find that more genes are differentially expressed between Y^M and III^M males in testis than head, and that genes with male-biased expression are most likely to be differentially expressed between Y^M and III^M males. This suggests that male phenotypes, especially those related to male fertility, are more likely to be affected by the male-determining chromosome, supporting the hypothesis that sex-specific selection acts on alleles linked to the male-determining locus driving evolutionary turnover in the sex determination pathway. We additionally find that III^M males have a "masculinization" gene expression profile, suggesting that the III^M chromosome has accumulated an excess of male-beneficial alleles because of its male-limited transmission. Overall design: 3 replicates of testes and male heads from a Y^M and a III^M strain, and one sample of head and ovary from each of the strains
Center Project: GSE67065
External Link: /pubmed:26142430