Fig. 5

piRNA and target transcript expression prior to and after the onset of zygotic transcription. a Heatmaps show the expression levels of putative piRNA targeted genes (piRNA RPKM ≥ 100), and the corresponding piRNA coverage prior to (M) and after (Z) the maternal-to-zygotic transition in T. castaneum embryos. Strand-specific piRNA levels are shown for intronic and exonic regions separately. Bargraphs (top) show the total normalized counts to each element. Black bars on the right indicate genes showing significant homology with TE-related sequences. b Scatter plots show the correlation of fold changes in mRNA and sense and antisense piRNA levels upon zygotic transcription activation (Z to M). Data points corresponding to transcripts with significant homology to TEs are black. Spearman’s correlation coefficients and associated p values are indicated. c Nucleotide biases for the first and tenth positions of sense and antisense piRNAs mapping to putative piRNA target genes (as in a and b) in maternal and zygotic small RNA libraries. Sequence logos for genes with more than twofold and less than twofold zygotically up-regulated piRNA levels are shown separately