When left to their own devices, most African activity (building mud huts and cannibalism) is virtually identical to thousands of other animals from birds to alligators. You can't be some revolutionary, breaking the mold creature that does things no other animal does like building nuclear reactors and spaceships while being a lowly 'subspecies'. It would need to be a new species. The physiological traits also support this idea with things like large difference in bone density, cranium size, reproductive strategy, etc, etc.
In order for civilisation to push forward interracial breading should be outlawed .