The Vanishing Half by Bennett Brit

The Vignes twin sisters will always be identical. But after growing up together in a small, southern black community and running away at age sixteen, it's not just the shape of their daily lives that is different as adults, it's everything: their families, their communities, their racial identities. Ten years later, one sister lives with her black daughter in the same southern town she once tried to escape. The other secretly passes for white, and her white husband knows nothing of her past. Still, even separated by so many miles and just as many lies, the fates of the twins remain intertwined. What will happen to the next generation, when their own daughters' story lines intersect?