[Overview of Circular RNA Research].

The fact that RNA could take circular form was discovered as early as 1 976.For a long peri-od,circular RNAs (circRNAs)had been viewed as outliners of transcripts.With the development of sec-ond generation RNA sequencing and bioinformatics,recent studies have revealed that circRNAs are prev-alent,with high degree of conservation,and with cell specificity in eukaryotes.Increasing lines of evi-dence indicate that circRNAs,rather than being noise of splicing,have essential biological functions in a seriers of regulatory events,and may even be related to the etiology of some human diseases.