Contents

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