The two reporters have the same expression pattern. Both are expressed in Z1 and Z4 of XO and XX L1 larvae. However, later during L1, the timing of expression is sexually dimorphic: in XO larvae reporter expression persists until late L1 in Z1/Z4 descendants, whereas in XX larvae it decreases in mid L1 and is undetectable by late L1. Later expression also is sexually dimorphic. In L3 hermaphrodites, the
fkh-6 reporters resume expression in sheath-spermathecal precursor cells, continuing through adulthood in spermatheca and weakly in proximal sheath. By contrast, no expression was observed in XO animals past the L1 stage. No expression was detectable outside the gonad in larvae or adults of either sex.