Figure 2.

Generation of small RNA sequencing libraries. The major steps from sample preparation to sequencing for small RNA molecules according to the Illumina protocol (Illumina TruSeq™ Small RNA Sample Preparation) are shown. The steps include adapter ligation, first strand cDNA synthesis, PCR-amplification, and sequencing. The regions of homology of the adapters involved are shown. The sequence of miR-99b-3p was chosen as an example. Read 1 indicates the sequencing cycles producing miRNA related sequence data. Read 2 indicates the production of index reads used for de-multiplexing of samples. Note that the miRNA related reads may contain adapter sequence at their 3′ end, which needs to be removed prior to downstream analyses.