In the presence of P{CP} sn^w mutates to sn^e and sn⁽⁺⁾. Transposase is also produced in the male and female germline, with or without heat shock sn^w mutability is high. The presence of Δ2-3 somatic transposase to Muller5-B X chromosome carrying five target P-elements causes pupal lethality, even without heat shock P{CP} can strongly repress the lethality. P{CP} fails to repress gonadal dysgenesis, either through a maternal effect or through a combination of zygotic and maternal effects, with or without heat shock. P{CP} cannot repress sn^w mutability in the male germline or the somatic instability of sn^w (males have patches of weak sn, extreme sn and wild-type bristles) with or without heat shock. P{CP} has no effect on the expression of the Ecol\lacZ gene of P{lacZ}sn^unspecified or P{lacZ}vas^unspecified.