In 2003, the anthropologist Duana Fullwiley spent six months observing a team of biomedical research scientists. The team wanted to find out whether genetic variation could affect how different people respond to drugs, and to do so, they recruited a group of racially and ethnically diverse research subjects. They were a diverse team themselves, with good intentions to address a worthy problem—it’s well known that different races suffer from health problems at different rates and can respond differently to treatments. If they could trace these discrepancies to genetic differences between races, the team reasoned, they could explain, and perhaps start...