Sex-biased gene expression in Drosophila melanogaster larvae

Genes with sex-biased expression in adults experience unique evolutionary dynamics. It is unclear, however, whether the selection pressures responsible for these well documented patterns also act upon genes with sex-biased expression in other developmental stages. To examine this, we measured expression in male and female Drosophila melanogaster larvae. Drosophila melanogaster wandering third instar larvae were sexed using the visible gonad. RNA was isolated from three replicate samples of male and female larvae and one sample each of adult males and females. RNA was prepared following the manufacturer's instructions, using single color labelling. Each sample/replicate was hybridized to one sector of the Agilent 4 sector array (a total of two arrays were used), with the following design: Array 1 had one larval male sample, one larval female sample, one adult male sample, and one adult female sample; Array 2 had two larval male samples and two larval female samples.