RNA cannot be sequenced directly with the PacBio system, but is first reverse transcribed into cDNA. The long reads, however, make it possible to fully detect and differentiate between alternative splice variants. A size-selection step is usually not necessary, but short or long transcripts can be enriched by selective bead purification if necessary. The results can be used for genome annotation or for the detection of rare transcripts. A quantitative analysis is currently not possible. A single Sequel II SMRT Cell is usually used for a human transcriptome.