Profiling of sex-biased expression in Drosophila species

Extensive sex-biased expression has been seen in multiple surveys D. melanogaster. We were interested in broadly sampling sex-biased expression of orthologs and species- or lineage-specific genes in the Drosophila genus. To appropriately assay gene expression in multiple species, we used custom microarrays designed against each of six species that broadly sample the phylogenetic space represented by the newly completed genomes (D. simulans, D. yakuba, D. ananassae, D. pseudoobscura, D. virilis and D. mojavensis) and an array designed against D. melanogaster to determine the overall patterns of sex-biased expression in those species and their chromosome linkage. Keywords: other PolyA+ mRNA in duplicate were isolated from 5-7 day old adult females and males of seven drosophila species. Male and female mRNA was labeled by Cy3 or Cy5 dye separately and hybridized simultaneously to the appropriate species-specific arrays. We performed at least four two-channel hybridizations for each species including two biological replicates and dye-swaps for each of them. Only single channels which passed stringent pre-processing quality control were used. A total of 67 channels of data were used in the final analysis.