A single-stranded RNA molecule with a nucleotide sequence complementary to a sense strand RNA, i.e., messenger RNA. The combining of sense and antisense RNA in a cell is a powerful silencer of gene expression. asRNAs occur naturally in many organisms (e.g., as small interfering RNAs (q.v.) or small temporal RNAs (q.v.). These natural asRNAs silence genes at the transcriptional, post-transcriptional, or translational level. asRNAs can also be experimentally introduced into a cell or organism by such means as transformation (q.v.) with an artificial gene that transcribes asRNA or by injecting double-stranded RNA (q.v.) into cells or embryos. This is a powerful means of creating loss of function mutations in distinct genes. See Morpholinos, RNA interference (RNAi), strand terminologies.
Subjects: Genetics and Genomics.