The ability to distinguish between races using human genome involves comparing sequences to those of people native to various areas of the world. Outside of genetic similarities, race truly does not exist.
To answer how much evolution affects humans, several scientific journals have stated that humans will evolve to become taller and have larger eyes. This will most likely happen, but at an even slower rate than it used to, simply because natural selection is no longer in full force because of technology that keeps people who would be considered non ideal alive, like myself (I have celiac disease and am often sick, which prevents “mating,” as it were. However, due to the technology that makes me aware of my condition and my ability to avoid gluten, I am now just as fit to mate as any person without celiac. In this way, nonfavorable genes are passed on. This is very good in that we do not doom those born with disability, but bad in that we don’t evolve, while the world around us does.