[[File:Summary of RNA-Seq.svg|thumb|500pxupright=2|''Summary of [[RNA-Seq]].'' Within the organisms, genes are transcribed and spliced (in eukaryotes) to produce mature mRNA transcripts (red). The mRNA is extracted from the organism, fragmented, and copied into stable ds-cDNA (blue). The ds-cDNA is sequenced using [[DNA sequencing#High-throughput methods|high-throughput]], short-read sequencing methods. These sequences can then be [[Sequence alignment|aligned]] to a reference genome sequence to reconstruct which genome regions were being transcribed. This data can be used to annotate where expressed genes are, their relative expression levels, and any alternative splice variants.<ref name="Lowe_2017" />]]
