Why Egyptians are not ‘Black’

Egyptian culture is thousands of years old, yet they never maintained perfect isolation from the nations among whom they lived. They have been conquered and they themselves have conquered many times. Invading armies brought hordes of soldiers, who would have left behind children. Given that Egypt is on the African continent, and given that there Egypt was conquered at least once by the their southern neighbors (the Nubians) at least once, why doesn't the average Egyptian have the features of, say, the average person from Sudan? To answer this requires a deep dive into history and biology. There are four factors that have the greatest effect. 1) They are a Mediterranean culture, 2) many phenotypes (e.g., skin, hair, and eye color) are controlled by multiple traits, 3) many lineages peter out over time, and 4) genetic recombination insures that most people will fail to pass on their DNA to their distance descendants even if their line is maintained.