Orhan Pelinkovic's Reviews > Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past

The idea of an existence of a pure human race is scientifically dead.

Geneticist, David Reich, discovers through the process of whole-genome sequencing that modern humans are a mixture of a variety of human species, where forty thousand years ago our planet was inhabited by multiple groups of archaic humans that were physically different.

Comparing ancient to modern human DNA, Reich finds that the non-African genome, fifty thousand years ago, which was a direct ancestor of modern humans, had almost 5 percent of Neanderthal origin, while non-African genomes today consist of nearly 2 percent of Neanderthal origin. Hence, Neanderthals and the archaic human interbred. This depletion of the Neanderthal genes is accomplished by natural selection, at the expense of the Neanderthals DNA, and perhaps due to the high infertility of this hybrid. A similar history is shared in Asia and Oceania with the Denisovans, where Neanderthals and Denisovans are cousins. With all these findings, can we conclude that modern humans are to some degree biologically different?

Reich's laboratory was able to trace through analyzing the ancient DNA that the people of the Yamnaya culture from the Eurasian Steppe around five thousand years ago migrated to Europe and to a significant degree replaced the majority of the then existing European population. Reich further hypothesizes that this could be evidence why the Northern European languages spoken today are so closely kindred i.e. as a consequence of the spread of a new culture at the same time.

Genomic data also traces that the descendants of Indians today are a mixture of ancestral people of West Eurasia and South and East Asia and that the spreading of the Yamnaya five thousand years ago could offer a clue on how these two regions and their languages are a part of the same Indo-European language family. What was also fascinating is that an Ancient North Eurasian population genetically contributes one-third of their ancestry of present-day Native Americans, while the natives of the Amazon share ancestry with the indigenous people of Australia, New Guinea, and Andaman.

Who We Are and How We Got Here (2018) reconstruct events of the human past that reveals the history of humankind's movements, interbreeding, and transformations, replacement, and extinction of populations. David Reich in my opinion is not quite the writer and storyteller as Siddhartha Mukherjee, hence, the narrative is not as compelling as it is in Mukherjee's The Gene: An Intimate History. On the other hand, Reich is a heavyweight in his field and his work has and will have a great impact on the future work of archaeologists, anthropologists, and linguists. I have been meaning to read this book for some time now, but reading Sense of History's excellent review of the book triggered me to buy and read it, and I am glad I did.