Heterozygotes are mostly wild-type but occasionally lack a gonad arm; segregate tm4567 homozygotes (larval/embryonic lethal) and rol-9 homozygotes (Rol). Pick non-Rol to maintain and screen for larval lethals (or by PCR) for tm4567 deletion. Reference: Large EE and Mathies LD (2014 Jan 8). G3, doi: 10.1534/g3.113.009852.