TABLE 1.

Classification of ncRNAs.

Type	Full name	Abbreviation	Size	Function
Housekeeper ncRNAs	Ribosomal RNA	rRNA	120–4,500 nt	Used as a scaffold for mRNA molecules to achieve protein synthesis
	Transfer RNA	tRNA	76–90 nt	Transfer of activated amino acids involved in protein biosynthesis
	Small nuclear RNA	snRNA	100–300 nt	Binding with protein factors to form nuclei karyon glycoprotein particles to perform splicing mRNA function
	Small nucleolar RNA	snoRNA	60–400 nt	rRNA of modification
Regulatory ncRNAs	MicroRNA	miRNA	21–23 nt	By complementary pairing of bases with the 3'-terminal untranslated region of the target mRNA
	Long non-coding RNA	lncRNA	>200 nt	Dose compensation effect, epigenetic regulation, cell cycle regulation and cell differentiation regulation
	Small interfering RNA	siRNA	20–25 nt	—
	Circular RNA	circRNA	100–10,000 nt	—