Most biotech firms have their origins in labs, but Eugene Chan dreamed up U.S. Genomics in the medical-school dorms and libraries of Harvard University. His goal: to find a quicker, cheaper, more precise way to analyze DNA so all patients might benefit from the discoveries of the Human Genome Project. Chan patented his idea for a device that would read a DNA sequence straight from a single molecule- and left medical school in his second year to found U.S. Genomics in Woburn, MA, to develop the technology. The company’s latest prototypes catch fluorescence-tagged DNA on nanoscopic posts, unfurling the coiled molecules. The molecules then flow one by one into a narrow channel where lasers and optical detectors “read” the bar-code-like patterns created by the tags. The device can now identify certain sequences within long stretches of DNA; Chan hopes it will produce letter-by-letter sequences by 2006. He has raised some $57 million and recruited such sequencing gurus as Celera Genomics founder J. Craig Venter to the firm’s board. “The machines he’s built probably have hundreds of different applications,” Venter says.