30 April 1999
Vol 284, Issue 5415

About The Cover

Cover image expansion

COVER The cryptochromes are photoreceptors through which cells respond to blue light. A Review by Cashmore et al. (p. 760) in the special section on Signal Transduction (beginning on p. 755) summarizes recent evidence that cryptochromes function not only in regulation of plant growth, but also in entrainment of the endogenous biological clocks of a broad range of organisms-from plants and insects to mammals. [Collage: concept by A. Cashmore, created by Ann Elliot Cutting]
Collage photo credits: fly, Nigel Cattlin/Photo Researchers; mouse, Gary E. Pickard; Arabidopsis, Jamie Hayden