Correct, there is no way to reliably determine race via genes or any other physical method, and biologically speaking race doesn't exist. But you can find gene

Correct, there is no way to reliably determine race via genes or any other physical method, and biologically speaking race doesn't exist. But you can find genes that determine phenotypes that people think are racially relevant (skin color, hair texture, eye shape, etc) and you could imagine a gene drive that could do bad things to people with those genes. Whether those people are always (or even primarily) identified as or identify with a particular race could only be awfully approximate, but the effects could still be really bad.