Genomic sequence encoding the open reading frames of B9d2 and tctn has been replaced by a loxP cassette containing a w^GMR.PH marker.

Df(2L)B9d2-tctnΔ mutant flies are viable; the males produce motile sperm and show only slightly reduced fertility compared to controls. No obvious defects are observed in the axoneme or the transition zone of chordotonal cilia on antennae, however sperm flagella do show weakly penetrant ultrastructural defects (broken or disorganized axonemes).