How does RNA-seq work?

An RNA-seq workflow has multiple steps.

The first step involves extracting the RNA to be sequenced. The extracted RNA population is then converted into cDNA (complementary DNA) by reverse transcription. This is followed by fragmenting the cDNA and adding adapters to each end of the fragments. After a process of amplification, size selection, cleaning up and checking for quality, NGS (next generation sequencing) is used to analyze the cDNA library, producing short sequences that correspond to all or part of the fragment from which it was derived. The library sequencing depth varies according to the purpose for which the output is intended to be used.