Developmental expression patterns of toolkit genes in male accessory gland of Drosophila parallels those of mammalian prostate.

Conservation of genetic toolkits in disparate phyla may help reveal commonalities in organ designs transcending their extreme anatomical disparities. A male accessory sexual organ in mammals, the prostate, for instance, is anatomically disparate from its analogous, phylogenetically distant counterpart - the male accessory gland (MAG) - in insects like Drosophila. It has not been ascertained if the anatomically disparate Drosophila MAG shares developmental parallels with those of the mammalian prostate. Here we show that the development of Drosophila mesoderm-derived MAG entails recruitment of similar genetic toolkits of tubular organs like that seen in endoderm-derived mammalian prostate. For instance, like mammalian prostate, Drosophila MAG morphogenesis is marked by recruitment of fibroblast growth factor receptor (FGFR) - a signalling pathway often seen recruited for tubulogenesis - starting early during its adepithelial genesis. A specialisation of the individual domains of the developing MAG tube, on the other hand, is marked by the expression of a posterior Hox gene transcription factor, Abd-B, while Hh-Dpp signalling marks its growth. Drosophila MAG, therefore, reveals the developmental design of a unitary bud-derived tube that appears to have been co-opted for the development of male accessory sexual organs across distant phylogeny and embryonic lineages. This article has an associated First Person interview with the first author of the paper.