The PIWI/piRNA response is relaxed in a rodent that lacks mobilizing transposable elements

(A) PCA of squirrel testis derived from the expression of all TE insertions (B) and young insertions (C). Differentially expressed squirrel TEs between the pre-PIWI expressed samples (P0, P2) and post-PIWI expressed juvenile samples (P8, P10, P13) calculated from all TE insertions (D) and young insertions (E). Red circles reflect differentially expressed TEs with an adjusted P-value <0.1. Positive log₂-fold change values reflect higher expression in pre-PIWI samples.