Gene-Chips is run by computational chemist Leming Shi, "a fan" of DNA arrays who works as a contractor for the Food and Drug Administration. The site's design is simple yet effective: It's one long page of text sprinkled with hyperlinks. Shi describes how the chips work, the basic setup (robotics for making chips, labeled DNA probes, fluorescence reader, software), who sells them, and applications, which include drug discovery and toxicology. Links to review articles and scores of academic labs and companies provide more details. Patrick Brown's page at Stanford, for instance, has a manual on how to build your own microarray maker. A Cornell site offers a slew of online review articles, and a National Institutes of Health page describes its microarray project. And in one interesting application, a University of Arizona lab used the chips to see which genes are turned on in spermatogenesis in C. elegans worms.