Alternative starts of transcription, several paralogues, and almost-fixed interspecific differences of the gene fruitless in a hemimetabolous insect.

In fruit flies, the gene fruitless (fru) governs the establishment of the potential for male sexual behavior. We partially cloned fru from a hemimetabolous insect for the first time and we compared fru among three closely related and acoustically communicating grasshopper species: Chorthippus biguttulus, C. brunneus, and C. mollis. The fru of grasshoppers is organized similarly to fru of holometabolous insects, with a BTB and Zn-finger domains separated by a nonconserved repetitive linker. As in Drosophila, several transcripts of fru are found in grasshoppers. We also present evidence for the coexistence of several copies of fru in the grasshopper genome. Within species these copies are almost identical and carry almost-fixed species-specific differences. This suggests that the paralogous copies of fru in grasshoppers do not evolve independently from each other.