16 April 2010
Vol 328, Issue 5976

About The Cover

Cover image expansion

COVER Fluorescence microscopy image showing fragmentation of chromosomal DNA (green) during programmed cell death or apoptosis in a Caenorhabditis elegans embryo. Chromosomes are stained blue and nuclear envelopes red. During apoptosis, the ribonuclease Dicer, known for its role in gene silencing, is converted to a deoxyribonuclease and initiates this DNA fragmentation process. See page 327. Image: Jay Parrish/University of Colorado