Mary-Claire King is Professor of Genome Sciences and of Medicine (Medical Genetics) at the University of Washington (Seattle, WA), who first described a single gene on chromosome 17q21 (which she named BRCA1) being responsible for breast and ovarian cancer in many families. This work, published in Science in 1990, also revolutionized the study of many other common, single-gene diseases that are inherited in nature, and led to the discovery of BRCA2.