The average IQ of a black African is approximately 70, which is more than two standard deviations below the white average of 100

Not only is there direct experimental evidence for a genetic component to racial differences in intelligence, there is also the fact that black Americans, who inhabit about the best environment available (and average 17–18% white ancestry, according to molecular anthropologists) have an average IQ no more than 85, still one standard deviation below the white average (the so-called IQ gap). It may actually be as low as 78, since black people with the lowest IQs may be under-represented in many samples.