So the root difference is that there are two main branches. One was in Africa spawned all the others, the other exists only in Africa.
Anyone know which areas of Africa correspond to which branch?
The branch that moved into the rest of the world has the least genetic diversity, but populated the rest of the planet.
I think the northern group was smaller, got lighter skinned and more Asian in facial structure (like Kung! bushmen today). Weather cooled off, some of northern group moved south and intermingled as others moved along the Red Sea coast to India and Australia and others moved north into Asia.
Years back someone or another postulated that humanity had gotten it's start out of the trees when the Great Rift Valley opened.
This cut the ones on the east off from the rest of Africa. They were now down wind of the rift, the fumes and the changes in topography stripped moisture out of the prevailing winds. This created an orological desert in what had one been a lush environment and forced humanity to grow up.
Imaging what this looked like. From their hell on earth, they could see the greenery across the rift, remembered when they lived in similar abundance, and know that they were now literally cut of from it by a valley filled with fountains of lava.
They must have sinned, and a vengeful God punished them by throwing them out of the garden of Eden and set His angels to guard the entrance with swords of flame.
See
Genesis 3:24
So he drove out the man; and he placed at the east of the garden of Eden Cherubims, and a flaming sword which turned every way, to keep the way of the tree of life.