The Worm Answers (Continued)

With clues from the worm research, scientists discovered that plants have a special RNA-dependent RNA polymerase (RDRP) that produces double-stranded RNA molecules when triggered by very high levels of mRNA. Acting on the highly abundant mRNAs produced from the added pigment genes, RDRP created double-stranded RNA molecules that shut down gene expression and thus reduced pigment.

Gene silencing mediated by double-stranded RNA has been named RNA interference, or RNAi.