Identifying candidatede novogenes expressed in the somatic female reproductive tract ofDrosophila melanogaster

Abstract

ABSTRACTMost eukaryotic genes have been vertically transmitted to the present from distant ancestors. However, variable gene number across species indicates that gene gain and loss also occurs. While new genes typically originate as products of duplications and rearrangements of pre-existing genes, putativede novogenes - genes born out of previously non-genic sequence - have been identified. Previous studies ofde novogenes inDrosophilahave provided evidence that expression in male reproductive tissues is common. However, no studies have focused on female reproductive tissues. Here we begin addressing this gap in the literature by analyzing the transcriptomes of three female reproductive tract organs (spermatheca, seminal receptacle, and parovaria) in three species - our focal species,D. melanogaster- and two closely related species,D. simulansandD. yakuba, with the goal of identifying putativeD. melanogaster-specificde novogenes expressed in these tissues. We discovered several candidate genes, which, consistent with the literature, tend to be short, simple, and lowly expressed. We also find evidence that some of these genes are expressed in otherD. melanogastertissues and both sexes. The relatively small number of candidate genes discovered here is similar to that observed in the accessory gland, but substantially fewer than that observed in the testis.