 The RNA interference pathway is often exploited in experimental biology to study the function of genes in cell culture and in vivo in model organisms . Double @-@ stranded RNA is synthesized with a sequence complementary to a gene of interest and introduced into a cell or organism , where it is recognized as exogenous genetic material and activates the RNAi pathway . Using this mechanism , researchers can cause a drastic decrease in the expression of a targeted gene . Studying the effects of this decrease can show the physiological role of the gene product . Since RNAi may not totally abolish expression of the gene , this technique is sometimes referred as a " knockdown " , to distinguish it from " knockout " procedures in which expression of a gene is entirely eliminated . 
