RNA interference posttranscriptional gene silencing by siRNA GO:0016246 Wikipedia:RNA_interference RNAi The process in which double-stranded RNAs silence cognate genes. Involves posttranscriptional gene inactivation ('silencing') both of transgenes or dsRNA introduced into a germline, and of the host gene(s) homologous to the transgenes or dsRNA. This silencing is triggered by the introduction of transgenes or double-stranded RNA (dsRNA), and can occur through a specific decrease in the level of mRNA, or by negative regulation of translation, of both host genes and transgenes. biological_process Note that this term refers specifically to posttranscriptional mechanisms by which small interfering RNAs down-regulate gene expression. Also consider annotating to other descendants of 'gene silencing by RNA ; GO:0031047'. posttranscriptional gene silencing by RNA