Abstract: Circular RNA (circRNA) is a new type of RNA molecule,which is formed from precursor mRNA by reverse splicing to form a covalently closed ring structure,and the lack of a cap structure and PolyA tail makes it stable and not easily degraded by nucleic acid exonucleases.With the rapid development of high-throughput sequencing and bioinformatics technology,many important regulatory function of circRNA in plant and animal life activity and disease occurrence have been explained,such as competitive binding of microRNA (miRNA),regulation of gene transcription,encoding of polypeptides,interactions with RNA binding protein (RBP),etc.In recent years,circRNA has become a hotspot in livestock and poultry genetic breeding because of their special structure and important regulatory role in gene expression.As an important livestock species with a long history of breeding in China,sheep not only have many varieties,but also are distributed all over the country,and are one of the most common livestock in people’s daily life.circRNA plays a regulatory role in various traits of sheep,such as fleece (wool),meat quality,lactation and reproduction,and circRNA mostly regulates the expression of related genes by acting as molecular sponges of miRNA,thus affecting various traits of sheep.Therefore,the authors summarize the origin,development,synthesis mechanism,biological function of circRNA and their recent applied research progress in important economic traits of sheep,so as to provide a scientific reference for in-depth investigation of the molecular regulatory mechanisms of circRNA in important traits of sheep.

Key words: circRNA; sheep; economic traits