Simplified view of sex-determining pathways in the branchiopod crustacean Daphnia and insects.
An ESD pathway in Daphnia is compared with GSD pathways in insect model species, honeybee (Apis mellifera ), Mediterranean fruit fly (Med. fly, Ceratitis capitata, ) and fruit fly (Drosophila melanogaster ). Conserved Doublesex and Transformer homologs are indicated with red and blue boxes, respectively. Phylogenetic relationships among the four species are shown above the pathways , , . CSD, complementary sex determiner; fem, feminizer; Am, Apis mellifera: Cc, Ceratits capitata; sxl, sex lethal; mya, million years ago.