Tonight, we resume our look at the genome, the science of D-N-A, the genetic code for life as we know it. We’ll look at recent advances — and setbacks — for the once promising field of genetic-based personal medicine, including the FDA’s decision to shut down medical predictions by 23-and-me, a well-known consumer genetic company. We’ll explain how genetics is helping doctors regulate dosage of the blood thinner Warfarin. And we’ll also explore how the genome has opened old debates about biology and race.