The silence of the genes

About two years ago, it was recognized that introduction of double-stranded RNA (dsRNA) had a potent effect on gene expression, in particular on mRNA stability. Since then, this process has been found to occur in many differe nt organisms, and to bear a strong resemblance to a previously recognized p rocess in plants, called cosuppression. Both genetic and biochemical studie s have started to unravel the mysteries of RNA interference: genes involved in this process are being identified and in vitro studies are giving the f irst hints of what is happening to both the dsRNA and the affected mRNA mol ecules after the introduction of the dsRNA.