Some have argued that this gap is genetic (and we certainly cannot rule it out); however, there is no conclusive evidence to support their claim that the IQ gap is genetic.
Well, the claim that IQ gap is genetic is easy to prove: you just have to find the genes responsible for that gap. Then, find subjects of multiple races with and without those genes and demonstrate that they have statistically significant difference in IQ.
Until they have done that, claims that gap is genetic are unscientific. Period.
In any case, I'm pretty sure that the genes that make you "black" are not the same genes that make you "smart". I can buy an argument that there can be some correlation (which also can be cultural), but our understanding of genes is pretty far from the point where we would be able to make such claims.