Practice question

Small RNA sequencing is a specialized RNA-seq workflow designed for non-coding RNAs of 18–40 nucleotides such as microRNAs and small interfering RNAs. After total RNA extraction, RNAs are size-selected by gel or beads to enrich the small fraction, followed by ligation of 5′ and 3′ adaptors that exploit the characteristic 5′ phosphate and 3′ hydroxyl ends. Reverse transcription and PCR generate libraries that preserve strand information. Unlike mRNA sequencing which depletes small RNAs through poly(A) selection and size exclusion, this approach accurately quantifies miRNA expression, isoforms, and modifications.