Fig. 2.
Characteristics of the neuronal piRNA fraction. (A) Size distribution of retrotransposon-derived small RNA clones with 5′U. Primary piRNA fraction was defined as 26- to 29-nt, 5′U clones mapped to retrotransposons. Endo-siRNA fraction was defined as 20- to 24-nt, 5′U clones (on removal of miRNAs and structural RNAs) mapped to retrotransposons and genes/pseudogenes (Fig. S4). (B) Secondary piRNA fraction was defined as 26- to 29-nt clones without 5′U but with an adenine (A) at the 10th position. (C) Relative abundance of top subfamilies of retrotransposon-derived small RNAs within various small RNA fractions from two biological replicates. Average ± range. Unpaired t test was used to test significance of difference between two sets. *P < 0.05; n.s., not significant.
