Elis, S., Desmarchais, A., Cardona, E., Fouchecourt, S., Dalbies-Tran, R., Nguyen, T., Thermes, V., Maillard, V., Papillier, P., Uzbekova, S., Bobe, J., Couderc, J.L., Monget, P. (2018) Genes involved in Drosophila melanogaster ovarian function are highly conserved throughout evolution. Genome biology and evolution. 10(10):2629-2642.
This work presents a systematic approach to study the conservation of genes between fruit flies and mammals. We have listed 971 Drosophila genes involved in female reproduction at the ovarian level and systematically looked for orthologues in the Ciona, zebrafish, coelacanth, lizard, chicken and mouse. Depending on the species, the percentage of these Drosophila genes with at least one orthologue varies between 69% and 78%. In comparison, only 42% of all the Drosophila genes have an orthologue in the mouse genome (p < 0.0001), suggesting a dramatically higher evolutionary conservation of ovarian genes. The 177 Drosophila genes that have no orthologue in mice and other vertebrates correspond to genes that are involved in mechanisms of oogenesis that are specific to the fruit fly or the insects. Among 759 genes with at least one orthologue in the zebrafish, 73 have an expression enriched in the ovary in this species (RNA-seq data). Among 760 genes that have at least one orthologue in the mouse; 76 and 11 orthologues are reported to be preferentially and exclusively expressed in the mouse ovary, respectively (based on the UniGene EST database). Several of them are already known to play a key role in murine oogenesis and/or to be enriched in the mouse/zebrafish oocyte, while others have remained unreported. We have investigated, by RNA-seq and RT-qPCR, the exclusive ovarian expression of 10 genes in fish and mammals. Overall, we have found several novel candidates potentially involved in mammalian oogenesis by an evolutionary approach and using the fruit fly as an animal model.