Abstract
The ability to repress P-element-induced gonadal dysgenesis was studied in 14 wild-type strains of D. melanogaster derived from populations in the central and eastern United States. Females from each of these strains had a high ability to repress gonadal dysgenesis in their daughters. Reciprocal hybrids produced by crossing each of the wild-type strains with an M strain demonstrated that repression ability was determined by a complex mixture of chromosomal and cytoplasmic factors. Cytoplasmic transmission of repression ability was observed in all 14 strains and chromosomal transmission was observed in 12 of them. Genomic Southern blots indicated that four of the strains possessed a particular type of P element, called KP, which has been proposed to account for the chromosomal transmission of repression ability. However, in this study several of the strains that lacked KP elements exhibited as much chromosomal transmission of repression ability as the strains that had KP elements, suggesting that other kinds of P elements may be involved.
