Six years ago, the National Institutes of Health placed its biggest ever bet on precision medicine, launching a study to enroll over 1 million participants in an ambitious data-gathering gambit unmatched in its scope and diversity. Since then, Americans from all walks of life have been showing up and handing over their blood, spit, and pee to the project, dubbed “All of Us.” From those samples, scientists have recovered a trove of new genetic information — more than 275 million never-before-seen DNA variants.