About 1,000 people are the basis of today’s 7.8 billion people

Razib Kahn writes that there is relatively very little genetic diversity among humans outside of the remaining hunter-gatherer communities in sub-Sahara Africa (such as Khoi, the San, the Mbuti, the Mbenga, the Twa and the Hadza). There may well have been several waves of migration out of Africa. The one which dominate human society grew out of demographic bottleneck 60,000 years ago. He writes:

93-98.5% of the ancestry of humans outside of Sub-Saharan Africa (among those with no recent Sub-Saharan African ancestry, obviously) derives from a breeding population of 1,000 to 10,000, which expanded rapidly 60,000 years ago (reaching Australia and Europe around 45,000 and 50,000 years ago, accordingly).

Those 1,000-10,000 human beings who made it through their ordeal, smuggled out in their nuclei all the genetic diversity 6.42 billion very-not-diverse humans among us today would have to draw on ever after. Take a native each from say Santa Fe, Stockholm, Shanghai, Ulaanbaatar in Mongolia, Uluru in the Australian outback and a Sentinelese person from the Andaman Islands and you behold a little of the amazing superficial variety of the human race. They and their relatives have peopled almost every corner of the earth. They speak a riot of different languages and they look nothing like one another. And yet, aside from a dash of Denisovan here and a trace of Neanderthal there, as far as we can tell, they all trace the entirety of their ancestry back to a single founder event about 60,000 years ago.

An event when just a tiny subsample of 1,000-10,000 humans of that day passed through a brutal, extended bottleneck. Whether it was in Africa or just after leaving the continent, they burst out of that dire strait and re-peopled the globe.

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