Over the last 2.5 million years there are 21 times that could have happened (at a minimum), and maybe as many as 100 times all things considered.
Most of the record of human development to handle colder and higher latitudes would have been destroyed in this process, or in the comings and goings of the Sahara desert.
It's noteworthy that sometimes the Middle Eastern arid zone is FAR LARGER and constitutes as big a desert as the Sahara ~ it has not always been the case that people could travel South from Central Asia back to Africa or to Sundaland.
The other day in reading about how fast the ability to confer lifelong lactase production can be passed into a population (they have a living example of a Sa'ami group that picked it up in about 5 generations), I realized that all but about 25% of Subsaharan Africans have that ability ~ which is traceable TO Northern and Western Europeans.
Those genes flowed South to Africa, not North to Europe. All the other genes could have done so as well.
There's little reason to imagine that "modern" development even occurred in Africa.
Thats a really interesting fact to know, I woder how the theorists who promote “Out of Africa” handle that argument. Its sounds pretty solid to me.
So much of science today is driven by political correctness.
The climate boondoggle being the greatest modern example, and the Omana Junta ready to milk it for personal millions in Cap N Trade.
The Chinese are on to their approach because they too genuinely believe that China is the cradle of ALL civilization. I am glad they are giving the Africa origin
school a run for their money.
The indiginous Europeans must have found a way to live in the glacial periods, one wonders where they went.It will be found one day, likely under the Mediterranean Ocean.