RNA extensions are templated. (A) RNA-seq analysis of the length distribution of RNA extensions. (B) An example extension product of the LR-3 oligonucleotide and a model for its formation. The LR-3 oligonucleotide sequence is in black, the extension sequence is in orange, the region complementary to the extension sequence is in purple, and priming bases are bolded. (C) For the LR-3 oligonucleotide, a table of the 10 most abundant extension products of at least 5 nt. Colors are as in B. Note that the percentages reflect the abundance of a specific extension product relative to all extension products and not just extension products of at least 5 nt. See Supplemental Figure S3B for the five most abundant extension products of less than 5 nt and Supplemental Table S2 for all extension products regardless of length and abundance.
