Contents

19 April 2002
Vol 296, Issue 5567

About The Cover

Cover image expansion

COVER A mouse embryo 10.5 days after conception stained to show the expression pattern of two proteins, HNF3b (blue) and neurofilament (green). A microscopy technique based on optical projection tomography generates a three-dimensional image (foreground) from fluorescent images of the embryo at multiple stages during rotation (background). 541 [Image: J. Sharpe and U. Ahlgren]