Patrick O'Reilly Brown (born 1954) is an American scientist and businessman who is the chief executive and founder of Impossible Foods Inc. and professor emeritus in the department of biochemistry at Stanford University. Brown is co-founder of the Public Library of Science, inventor of the DNA microarray, and a former investigator at Howard Hughes Medical Institute. Education Brown received each of his degrees from The University of Chicago, including his B.S. in 1976 and M.D. in 1982. His Ph.D., granted in 1980 while under the guidance of Nicholas R. Cozzarelli, involved the study of DNA topoisomerases. Academic career After getting his medical degree in 1982, Brown completed a 3-year pediatric residency at Children's Memorial Hospital in Chicago but decided he could have a greater impact through basic research. In 1985, Brown took a 3-year postdoctoral fellowship at the University of California, San Francisco with J. Michael Bishop and Harold Varmus (who shared the 1989 Nobel Prize in Medicine for their discoveries about how genes can ignite cancerous tumors). At UCSF, Brown and colleagues defined the mechanism by which retroviruses, such as the AIDS virus, integrate their genes into the genome of the cells they infect, which helped lead to development of new drugs to fight the disease. In 1988, Brown became an investigator of the Howard Hughes Medical Institute and an assistant professor in the Department of Biochemistry at Stanford University School of Medicine, where he continued to investigate retroviral replication. In the early 1990s, Brown began developing a new technology to enable systematic investigation of the behavior and properties of whole genomes—called DNA microarrays. "I had a mental image of a DNA microarray, even including the red and green fluorescent spots, a few years before I'd figured out the details of making them," Brown told The Scientist. Brown and his colleagues created a robotic dispenser that could deposit minute quantities of tens of thousands of individual genes onto a single glass slide, a “DNA microarray” or "gene chip." By flooding the slide with fluorescently labeled genetic material derived from a living sample, a researcher could see which genes were being expressed in cells. Shortly after their first description of DNA microarrays, the Brown laboratory published a “how-to” manual on the Web that helped these robotic devices become standard equipment in life science labs throughout the world, in an effort led by Joe DeRisi, Michael Eisen, Ash Alizadeh, and others.