'Race' is a dumb concept. We know that there are groups of people that are biologically distinct from others. Not to say that they can't interbreed, merely that there are genetic/phenotypic differences between groups.

Probably the most obvious example is http://en.wikipedia.org/wiki/Sickle-cell_disease#Epidemiolog... which is a condition that mostly appears in people with ancestry in regions that expose them to malaria.

Skin color is obviously a biological difference that distinguishes different human populations, it just doesn't correlate with all the stuff we actually care about, for instance intelligence. 'Race' is loosely correlated with some specific biological traits, for instance http://www.webmd.com/hypertension-high-blood-pressure/guide/...

As for hyper-successful people breeding themselves into a sub-group with specific traits, for better or for worse, this is obviously possible http://en.wikipedia.org/wiki/Prognathism#History