Fig. 7

Proposed models for the mechanisms by which the respective paternal genome protects daughters and granddaughters from P-element-induced gonadal dysgenesis. Schematic representation of transcriptionally active (light gray box) and silent (oblique-line box) regions, piRNA clusters (dark gray box), and P and KP elements (thick vertical lines) in the maternally (Mat) and paternally (Pat) inherited genomes, as well as their interactions in F1 and F2 hybrid ovaries. The name of the strain used as the male parent of the F1 progeny are indicated on the left. Short and long wavy lines represent P-element piRNAs and P-element mRNAs, respectively. Repressive effects are represented by a thick line with an inverted T (inverted T line), where thickness indicates the strength of suppression. Arrows show the transposition of P elements. Dotted lines from F1 to F2 hybrids show maternal deposition of piRNAs