20 December 2002
Vol 298, Issue 5602

About The Cover

Cover image expansion

COVER Researchers are discovering that small RNA molecules play a surprising variety of key roles in cells. They can inhibit translation of messenger RNA into protein, cause degradation of other messenger RNAs, and even initiate complete silencing of gene expression from the genome. See the Breakthrough of the Year special section and the accompanying Editorial. 2296 [Illustration: Cameron Slayden]