Project description:Transcript abundance was measured in whole-body virgin male Drosophila serrata from 41 inbred lines that had diverged through 27 generations of mutation accumulation that were sexually selected Sexual selection is predicted to have widespread effects on the genetic variation generated by new mutations as a consequence of the genic capture of condition by male sexual traits. We manipulated the opportunity for sexual selection on males during 27 generations of mutation accumulation in inbred lines of Drosophila serrata, and used a microarray platform to investigate the effect of sexual selection on the expression of 2685 genes, representing a broad coverage of biological function. Sexual selection had little effect on mean gene expression levels, with only 4 genes diverging significantly at a false discovery rate of 5% . In contrast, sexual selection impacted on both the magnitude and nature of mutational variance accumulating in these genes. The magnitude of mutational variance increased under sexual selection by an average of 29%. Mutational variance was less commonly generated by extreme phenotypes less commonly under sexual selection. Furthermore, analysis of random sets of five genes revealed that the mutational variance that accumulated under sexual selection was less pleiotropic in nature than that found in the absence of sexual selection. The generation of greater mutational variance without a general concomitant change in mean expression under sexual selection suggested that gene expression traits were be under apparent rather than direct sexual selection. We discuss two main explanations for the broad-based increase in mutational variance under sexual selection that both require extensive pleiotropy between traits affecting male mating success, standard metric traits represented here by gene expression traits, and general fitness. We measured gene expression of male Drosophila serrata from 41 mutation accumulation lines (whole-body) that were sexually selected. Data from two replicates for each line are presented.
Project description:MicroRNAs (miRNA) are small, endogenous RNAs that regulate the expression of mRNAs posttranscriptionally. Evolutionarily new miRNAs, like new protein-coding genes, are dominantly expressed in reproductive organs. To dissect the evolutionary dynamics of new miRNAs in Drosophila spp, we sequenced small RNAs from two species of Drosophila, including four samples from reproductive organs and one sample from imaginal discs / CNS. miRNA expression profile shows vast majority of new miRNAs are specifically expressed in testes and/or ovaries, suggesting a role of sexual selection for new miRNA evolution.
Project description:Sexual selection on males is predicted to have widespread effects on genetic variation as a consequence of the pleiotropic allelic effects on sexual and non-sexual traits. We manipulated the opportunity for sexual selection on males during 27 generations of mutation accumulation in inbred lines of Drosophila serrata, and used a microarray platform to investigate the effect of sexual selection on the expression of 2689 genes. While gene expression signal was, on average, higher in the absence of sexual selection, this difference was small (0.1%). In contrast, sexual selection impacted substantially on the mutational variance in gene expression. Over all genes, mutational variance in gene expression was, on average, 42% higher when sexual selection operated than when it was absent. Our results indicate that sexual selection on males can generate widespread effects across the genome. An increase in mutational variance without a corresponding change in mean suggested that most expression traits were unlikely to be under direct sexual selection. Instead, the mutational variance in gene expression traits is consistent with divergence generated by widespread pleiotropic associations with traits affecting male mating success.
Project description:MicroRNAs (miRNA) are small, endogenous RNAs that regulate the expression of mRNAs posttranscriptionally. Evolutionarily new miRNAs, like new protein-coding genes, are dominantly expressed in reproductive organs. To dissect the evolutionary dynamics of new miRNAs in Drosophila spp, we sequenced small RNAs from two species of Drosophila, including four samples from reproductive organs and one sample from imaginal discs / CNS. miRNA expression profile shows vast majority of new miRNAs are specifically expressed in testes and/or ovaries, suggesting a role of sexual selection for new miRNA evolution. Five small RNA samples, mainly from reproductive organs of D. simulans and D. pseudoobscura were analyzed. The small RNAs were sequenced by Illumina HiSeq 2000. After triming the adapters, the 18-30 nt sequences were extracted for further study.