scRNA-Seq provides deeper insight to the multi-tiered complexity of different cells within the same tissue type. scRNA-Seq has now been adapted widely into other methods in the single-cell RNA sequencing field. In this method, single cells are isolated manually under a microscope and lysed. Next, mRNAs are purified and primed with a poly(T) primer for reverse transcription. Unreactive primers are removed by exonuclease I digestion. Poly(A) tails are added to the first strand cDNA at the 3' end and annealed to poly(T) primers for second-strand cDNA generation. Finally, the cDNAs are PCR-amplified, sheared, and prepared into sequencing libraries.