A story on science news.com gives an accessible account of an article published in Science about a genetic study from the genome recovered from a boy who lived in southern Africa 2000 years ago: https://www.sciencenews.org/article/ancient-boys-dna-pushes-back-date-earliest-humans. The methodology here is way beyond my ken but it involves comparing this genome to others recovered all around Africa and Eurasia from different time periods and figuring out rates of genetic change that would account for its composition some 2000 years ago. The scientists concluded that the essential genome for us, Homo sapiens, coalesced around 350,000 years ago; that is a 100,000 years earlier than previously thought.
Putting some of the reports together, it seems that humans in Africa long ago traveled the length and breadth of the continent and intermarried for many thousands of years ago before modern humans migrated to Europe, maybe influenced by climate changes.. My 6/19/17 post was about a Moroccan fossil that also put Homo sapiens origin around 300,000 years ago. For reference DNA studies indicate that Neandertals and Denisovans (our kinfolk in Europe and the Russian steppe; homo sapiens did not arrive in Europe until around 30,000 years ago) split around 640,000 years ago.
Adding to a post from some time back check out these dates listed as years ago:
3 million—gene appears promoting brain enlargement
2 to 2.8 million—tools that were worked and shaped
1.8 million—fire and cooking (homo erectus)
before 640,000-Neandertal and Denisovan genomes took shape
500,000–phonological study’s estimate of origins of modern language
350,000-Homo sapiens genome took shape
130,000-eagle claw necklace from southern Africa
40,000 to 100,000—burials
45,000—paintings, good painting they are too
40,000—modern humans arrive in Europe
9,000—dog burials (just found that one)
6,000—glyphs and a new learning curve
500–modern science took hold
And so we travel on.