Workflow and results, with numbers and percentages of genes of testis interest in the species studied. Step 1: selection of 379 fruit fly genes with functional interest for testis. Step 2: retrieval of their orthologs (“phylogenetic filter”) in vertebrates, including mice, for a total of 625 mouse orthologues. Step 3: to tighten the list, selection of genes with a high relative testis expression (“preferential testis expression filter”) and their paralogs (scored in Flybase for their orthology link) to obtain a final list of 68 mouse genes of interest, gathered in 28 groups of paralogs. Step 4: identification of chicken and zebrafish orthologs (144 and 60, respectively) of these mouse genes, and finally, the determination of their levels of relative testis expression (fifth step). Genes conserved across evolution exhibiting an arbitrary level of rTE ≥ 50% in a species were considered genes of interest for testis function in this species.