All Caucasians whether they are Europeans, Arabs or Central Asians originate from a single tribe that live in the central Asian region of Eurasia around forty thousand years ago. The reason that the people of the Horn of Africa look somewhat different than other aboriginal Africans is geography. It is only a short distance across straights and the red sea to the Arabian peninsula, home of the Caucasians Arabs. They have been crossing the sea, visiting Africa and leaving their DNA for at least the last two thousand years