Fig. 2

Expression of piRNA and mRNA of P elements in F1 embryonic bodies of F1 progenies in cross A*. a Small RNA reads (23–35 nt) mapped to the sense (green) and antisense (red) strands of the P element are shown on the P-element structure (bottom). Har (top) was a P strain as a control. b Frequencies of length (0–25 bp, x-axis) of overlapping regions between sense and antisense small RNAs (23–35 nt) identified in F1 embryos. An overlap of 10 bp is a signature of piRNA pairs produced via the ping-pong cycle. c The expression levels of ping-pong-paired piRNAs in F1 ovaries (reads per million [RPM] miRNa reads). The strain names of mothers are shown in black (P), red (M′), and blue (Q). d The relationship between the log expression levels of mRNAs (y-axis) and piRNAs (x-axis) of P elements in F1 ovaries. The strain names of mothers are shown in black (P), red (M′), and blue (Q). The Pearson’s correlation efficient is shown on the top