Maybe you could tell us why the greatest poet ever to write in any IndoEuropean language (Pushkin) was a man of color or how his great grandfather, a pure African kid given to Tsar Peter by the sultan of Turkey became a major minister in Tsar Peter's court, or how Scott Joplin became the greatest American composer of piano music, or how.....
Science and bullshit don't really mix well.
There is a thing called a Distribution Curve. In any subgroup there are people at the right end of the curve, people in the middle, and people at the left end. The highest-IQ people of subgroup A are going to be smarter than the average person in subgroup B, even if the median IQ of subgroup B is more than the median for A.