Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past

Who We are and How we Got Here explores the history of the species by analyzing ancient DNA. The tools and statistical techniques are all new and as a consequence, this is quite a cutting edge book. The author is a professor of genetics at Harvard, and over the last decade has been working with applied mathematician Nick Patterson to analyze ancient DNA to understand our species ancient migrations as well as how genetic mixes occurred. The book introduces effectively revolutionary ideas to the fields of archaeology and anthropology which have historically had to rely on weaker more subjective inferences that, with new evidence, are seen to be more error prone. The author explores both human origins as well as the last 15k years where there is more substantial skeletal evidence to analyze. It is an impressive work with impressive breadth.The book is split into three major sections, with the second being the most substantial/ The author starts with some quick biology and discusses the genome and the way in which it can be used to understand various relationships. The author also brings up the somewhat common knowledge notion of humanity coming from Africa to start the discussion of the human genome's origin. The author then spends the rest of the first part on the most ancient DNA samples that has been analyzed namely Neanderthal and Denisovan DNA and how traces of both of those pre-modern human species are partially embedded in large parts of today's population. The author then analyses many various cultures DNA today to infer the migratory patterns of various cultures as potential explanations for the current distribution of genome's proportion of various proto-human species. There is a lot of material in not a huge amount of pages so things are reasonably compactly outlined. The author then gets into the most substantiated parts of the book which are inspections of various ethnic groups DNA alongside ancestral sampled DNA. The author discusses India, various native American cultures with chapters on East Asia and Africa as well. The analysis is more complete for India and Native American populations as there has been better access to DNA samples but one learns that the caste system has preserved ancient DNA lines such that they are visible to analysis today. Furthermore there were effective two distinct people who made up most of the DNA mix of today and the proportions can be seen in caste divisions with Indo-European being of higher caste. For Native Americans one learns that there was an earlier crossing by early humans before the land bridge was fully formed and thus there were two ancient people who compose all of native North and South American people. Due to restrictions on exporting biological material in China, the techniques developed by the author and in the West have not been used and in Africa there has not been enough material to analyze yet to get as clear a picture as the author would like but one learns of the genetic diversity of Africa as well as the abundance of different sub-populations. The author finishes with an overview of the work and its repercussions. He spends a lot of time discussing the ethical implications of understanding our origins as well as the hesitancies of many academics to stomach the reality that the genome can highlight racial differences. This part of the book is readable but somewhat irrelevant to the major core which is to better understand human migration and mixing of the past rather than the ethical spillovers of reading the genome as a general exercise.This is an impressive new field and the author communicates his results well. That being said each of the sections could be a several hundred page book so this being condensed leaves a lot of material out. There are many areas where the author states a statistical inference from some new test they have developed where the result does not follow directly from the previous statement so one has to just take it at face value. That is to the benefit of the reader but just indicative of much having to be left out to cover the ground. One can understand from reading this how the authors work is groundbreaking and will re-shape our understanding of ourselves over time.

It is humans, according to the Sophists, that make things good or bad. And, granting certain exceptions, this is largely true. David Reich’s book “Who We Are and How We Got Here” proves this ancient observation yet again with regard to the power of DNA technology. He also demonstrates that human nature is immutable, though in a way he perhaps didn’t anticipate. Reich begins the book by providing a readable, succinct primer on biology and DNA, which is essential to someone like me bereft of training in those fields. He quickly moves into the meat of the book and discusses what DNA technology can and can’t tell us about how humans become human and the past movements of peoples. It turns out that it can tell us quite a lot while still leaving large, possibly unanswerable questions before us. One debate that DNA has settled is the question of whether Neanderthals and homo sapiens interbred. That answer is a flat “yes.” Non-African humans contain up to two percent Neanderthal DNA and East Asians contain even a bit more. DNA also confirmed the existence of the Denisovans, a hominin that split off the lineage that also produced Neanderthals and humans. Finally, the use of DNA put to rest the theory that modern humans evolved into one common species in several locations throughout the world. In fact, modern humans evolved first in Africa and spread thence, eventually outcompeting other hominid beings and dominating the planet. The book is dense with facts that I prefer to leave them to the reader to discover rather than hastily relate them in a review. The story of how Europeans became European, the origins of modern Indians, and how the Americas were populated is all here. In addition, the reader will learn how and why certain diseases get transmitted through certain populations at higher rates than others. My one gripe with the author is he can’t resist scoring political points and virtue signaling at the expense of a great man and in the process tarnishes his own honor. Reich starts off well. He is preoccupied throughout his book that some will take the power of DNA research and pervert it towards a malign end. After all, this is precisely with the Nazis did, using pseudoscience to justify race war. In contrast, Reich uses DNA evidence to puncture some of the still extant race myths and pleas for the responsible use of the technology. But then he turns to James Watson, the codiscoverer of DNA’s structure, and a whispered discussion they once had at a conference in 2010. Apparently- allegedly- Mr. Watson made a few benighted observations about Indians and East Asians. If true, the comments were certainly distasteful; but they were whispered to Reich, clearly something not intended for wide broadcast. They were said in confidence by a man who was 82 years old at the time. By retailing them in a book Reich looks to be scoring cheap points against a titan of his field and reveals himself to be at once a grandstander and a jealous upstart. It’s simply poor form and completely unnecessary to proving his larger point. Overall, this is a decently-written book with valuable information. It is essential reading if one wants to know the history of the human being whose nature, as Reich unknowingly demonstrates, does not change.

L'autore non si nasconde dietro il politicamente corretto e non ha paura di discutere di differenze genetiche tra le popolazioni umane. Reich sottolinea giustamente che il fatto che la genetica venga a volte abusata da persone o gruppi razzisti non deve fermare la ricerca scientifica, che potrebbe ad esempio portare benefici rivoluzionari nella cura di molte malattie.

This fascinating book carries forward from previous works on ancient DNA and puts to rest competing theories on the genetic makeup and history of Europe, the Americas, Asia and the Indian subcontinent. The author does a good job of discussing ethical issues and cultural sensitivities. The big contribution this books brings to its audience is explaining the ghost populations of the past and how these populations explain some of the strange results we see in ancient DNA. For those interested in Ancient DNA and genetic anthropology this book is a real page turner.

Es una excelente síntesis del apasionante desarrollo actual del análisis genómico, por uno de sus principales protagonistas. Cualquiera que esté interesado en el origen y evolución de homínidos y humanos lo disfrutará muchísimo.

Amazing!

Es lo más reciente en la utilización del ADN para conocer la prehistoria. Explica las migraciones en los tiempos antiguos con mucha solvencia, ampliando enermemente lo que hasta ahora sabíamos sobre el tema. A veces el lenguaje es técnico pero sin duda vale la pena.