Human evolution; lots of genetic mixing (Introduction)

by David Turell , Thursday, March 19, 2020, 20:56 (1708 days ago) @ David Turell

A new broad study of many populations:

https://www.newscientist.com/article/2238034-dna-analysis-reveals-just-how-intertwined-...

"Bergstrom and his colleagues sequenced the genomes of 929 people from 54 different populations across the globe, including in Europe, the Middle East, Africa, America, Central and South Asia, East Asia and Oceania.

"They discovered hundreds of thousands of new gene variants that were common in many of the populations they studied but that had previously been missed, due to a lack of DNA sequences from people of non-European descent in existing data sets.

"Among the new discoveries that Bergstrom and his colleagues made was the finding that there was probably much more mixture between different ancient human populations in Africa than suggested by previous studies. Rather than a diverging family tree, they found evidence for much more gene flow between different populations. “It’s more like a kind of intertangled mesh of branches,” says Bergstrom.

"This hints at how ancient humans migrated out of Africa. Rather than a population separating into two and never seeing each other again, people probably continued to move between groups in a much more complex way, he says.

"The team also found more detailed evidence of our ancient human ancestors mating with other hominids. We already knew that our ancestors mated with archaic human groups, including Neanderthals and Denisovans, but until now it wasn’t clear how frequently this occurred and whether they mated with some groups more than others.

"Bergstrom and his team were able to show that people from many different populations around the world today have the same segments of Neanderthal DNA in their genomes, but segments of Denisovan DNA differ between people in different populations. That suggests that our ancestors probably mated with a single Neanderthal group but with multiple Denisovans after migrating out of Africa."

Comment: My interpretation remains the same: God used the adaptive abilities of the various human groups to result in a final group of sapiens well prepared for a variety of climates, and infectious processes.