The Worm Answers

For 10 years, the results in petunias perplexed scientists. However, researchers working on the worm Caenorhabditis elegans found that injecting double-stranded RNA turned down the expression of genes with a matching nucleotide sequence. Double-stranded RNA seemed to be critical for gene silencing.

Microscopic images of three worm heads, one of which fluoresces green.
The heads of three C. elegans. The pharynx of one worm fluoresces green due to an inserted gene.