Egyptians trace back to what?
Do you mean where did the Ancient Egyptians come from? There’s some evidence to suggest there were lots of peoples, with some very crude sculpture and other stirrings of civilization, living at oases scattered around the Sahara. Those oases dried up as the Sahara dried out, about 6-7000 years ago if I remember right. Some of them migrated east and settled along this big river, and that seems to have formed the origins of Ancient Egypt. They most likely mixed with peoples who were already there, and/or with the ancestors of the Kush to the south.
