Genes Involved in Drosophila melanogaster Ovarian Function Are Highly Conserved Throughout Evolution

Abstract

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 orthologs in the Ciona, zebrafish, coelacanth, lizard, chicken, and mouse. Depending on the species, the percentage of these Drosophila genes with at least one ortholog varies between 69% and 78%. In comparison, only 42% of all the Drosophila genes have an ortholog in the mouse genome (P < 0.0001), suggesting a dramatically higher evolutionary conservation of ovarian genes. The 177 Drosophila genes that have no ortholog 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 ortholog 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 ortholog in the mouse; 76 and 11 orthologs are reported to be preferentially and exclusively expressed in the mouse ovary, respectively (based on the UniGene expressed sequence tag 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, whereas others have remained unreported. We have investigated, by RNA-seq and real-time quantitative PCR, 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.

An evolutionary approach to recover genes predominantly expressed in the testes of the zebrafish, chicken and mouse

“…The high rate of conservation (83%) found for testis genes between invertebrates and vertebrates is significantly higher than the 42% expected for the complete fruit fly genome and similar to that found for genes involved in ovarian function in our previous study (78%) [15]. This high rate is in accordance with the conservation of germ cell differentiation [1].…”

“…This was also true for the mouse species. For example, and as described in our previous work [15], tdrd5 and rnf17 are highly expressed in the zebrafish testis and ovary, similar to their mouse orthologs. This finding suggests a common function in male and female germ cells for these conserved genes across evolution.…”

“…In the present study, we propose a comparative biological approach combining phenotypic, phylogenetic and expression profile analyses in invertebrate and vertebrate species, based on our previous work on ovarian genes [15]. Here, we aimed 1) to obtain an overview of testicular gene conservation between invertebrates (fruit fly) and vertebrates (mouse, chicken, zebrafish); 2) to obtain an overview of the expression profiles of conserved testicular genes in vertebrates and 3) to propose new (i.e.…”

A Comparative Analysis of Oocyte Development in Mammals

“…This meta-analysis revealed a remarkably high proportion of conservation, as 78% of these genes have at least one ortholog in the mouse, as compared to 42% of all genes in the fly genome. Approximately 15% of these mouse orthologs are expressed exclusively or most preferentially in the oocyte as compared to other cells [38]. Beyond meiosis, several functions such as mRNA binding seem to be highly conserved in oocytes from nonvertebrates to vertebrates [38,39].…”

“…Cells 2020, 9, x 4 of 26 of these mouse orthologs are expressed exclusively or most preferentially in the oocyte as compared to other cells [38]. Beyond meiosis, several functions such as mRNA binding seem to be highly conserved in oocytes from nonvertebrates to vertebrates [38,39].…”