1996 Researchers start putting DNA chips to the test. In 1996, Francis Collins of the National Human Genome Research Institute in Bethesda, Maryland, uses an Affymetrix microarray to detect mutations in the breast cancer gene BRCA1 in women at risk for the disease. Within a year, Brown and his colleagues synthesize the first chip containing all 6,000 yeast genes. The chip enables researchers to track which genes are switched on (or off) as yeast cells grow, divide, form spores, or defend themselves against poisons. For the first time researchers are seeing global "gene-expression patterns," with whole clusters of genes turning on and off together to orchestrate the activities of a living organism.