02 June 1989
Vol 244, Issue 4908

About The Cover

Scanning tunneling microscope images of an uncoated DNA fragment adsorbed on a single-crystal gold surface under water. The image, which has been repeated in a chevron pattern, is 700 Å by 700 Å and is viewed at an angle of about 45° with respect to the surface. The individual 36 Å twists of the helix backbone can be seen. See page 1063. [Photograph courtesy of S. M. Lindsay, Department of Physics, Arizona State University, Tempe, AZ 85287]