Identification of small RNAs and associated proteins in Caenorhabditis species. (A) Bar graphs show the size and 5′ first nucleotide distributions of small RNAs. (Insets) Pie charts display the proportion of reads belonging to different classes of small RNAs: miRNAs, piRNAs, and siRNAs, or unclassified. (B) Phylogenetic relationship of the elegans group of Caenorhabditis, adapted from Kiontke et al. (2011). C. briggsae, C. remanei, C. brenneri, and C. elegans (highlighted in red), having had their genomes sequenced and partially annotated, were chosen for this study. (C) Phylogeny of RNA-dependent RNA polymerases. Genes from different species are color-coded, and different subfamilies are indicated by colored branches. (Cel) C. elegans, (Cbr) C. briggsae, (Cre) C. remanei, (Cbn) C. brenneri. (D) RT-PCR of rrf-4 from mixed-stage C. briggsae, C. remanei, and C. brenneri.
