H{hsp/CP} produces functional P\T in both the male and female germline, but not in the soma. Heat shock treatments significantly increase transposase activity in the female germline but have little effect in the male germline. The P\T transposase activity encoded by H{hsp/CP} is repressed by the P cytotype. The H{hsp/CP}2 insertion reduces the transposase activity of P{Δ2-3}99B in the germline and in the soma. Paternally derived H{hsp/CP} transgenes do not induce gonadal dysgenesis in the offspring of M females or the offspring of P females, but do induce gonadal dysgenesis in the offspring of M' females.

H{hsp/SP} has no effect on the P\T^CP.hs transposase activity encoded by H{hsp/CP}2; H{hsp/CP}2 produces similar rates of sn^w mutation (in the absence of heat shock) in the male germline whether or not H{hsp/SP} is present. H{hsp/BP1} has no effect on the P\T^CP.hs transposase activity encoded by H{hsp/CP}2; H{hsp/CP}2 produces similar rates of sn^w mutation (in the absence of heat shock) in the male germline whether or not H{hsp/BP1} is present. H{hsp/KP} represses the P\T^CP.hs transposase activity encoded by H{hsp/CP}2; the rate of sn^w mutation in the male or female germline caused by H{hsp/CP}2 is reduced if H{hsp/KP} is present. P{KP}2F represses the P\T^CP.hs transposase activity encoded by H{hsp/CP}2; the rate of sn^w mutation (in the absence of heat shock) in the male germline caused by H{hsp/CP}2 is reduced if P{KP}2F is present. P{KP}13F does not repress the P\T^CP.hs transposase activity encoded by H{hsp/CP}2; H{hsp/CP}2 produces similar rates of sn^w mutation (in the absence of heat shock) in the male germline whether or not P{KP}13F is present.

The mutation rate of sn^w (measured by scoring the ratio of sn^w mutant phenotypes to extreme or wild type sn phenotypes in the progeny of the male flies in question), a P-element insertion allele highly mutable by P\T^CP.hs is dependent on the mode of inheritance ofP\T^CP.hs : 1. The transposase activity of P\T^CP.hs is transmitted by maternal effect: there is a significant sn^w mutation rate due to maternal P\T^CP.hs in flies zygotically lacking P\T^CP.hs (the rate for sn^w in a wild-type background is near zero). 2. For flies with a zygotic copy of P\T^CP.hs : Males that inherit P\T^CP.hs from their mothers have a significantly higher mutation rate for sn^w than those who inherit it from their fathers. 3. For flies without zygotic P\T^CP.hs : Males whose grandmothers had P\T^CP.hs and who inherit it from their fathers have a significantly lower sn^w mutation rate than equivalent flies whose grandmothers did not carry P\T^CP.hs.