DNA USA: A Genetic Portrait of America

Abstract

DNA USA: A Genetic Portrait of America Bryan Sykes Liveright Publishing, 2012The premise of the current book is highly intriguing - an attempt to identify the ancestral origins of the various peoples that inhabit present-day USA by genetic analysis - even though it ultimately fails to deliver the promised "genetic portrait of America" in that it largely ignores the Asian component, which is annually increasing in importance. The centerpiece comprises "chromosome portraits" of selected and supposedly representative individuals. A chromosome portrait involves probing autosomes (chromosome pairs excluding the sex chromosomes) for specific genes with single nucleotide polymorphisms that correspond to one of "three continental origins" (Asia, Africa and Europe).This is a book written for the layman who will find it interesting, but out of the whole book, about half is really worthwhile from the standpoint of general science. However, the layman will find that the process of using genes to uncover ancestry is described in easy to understand terms - it is to Sykes' credit that he uses simple language to describe concepts that someone with little background in genetics could understand. The author describes the genetic linkage between today's Native Americans and Asians through DNA analysis, thereby tying Native Americans to Asia. While Native Americans originated from outside the Americas and the author recites what is known about their prehistoric migration believed to be via the Bering Straits at a time when the ocean levels were much lower than today.The other half of the book however consists of recitation of oftenopinionated personal musings that may or may not have anything to do with genetics as the author travels across America in search of test subjects. Indeed, he includes photographs of himself and his colleagues snapped at different places along his route. Notwithstanding that the U.S. has nowhere near an efficient railway system as operates in Europe or Japan, the author chooses to travel by Amtrak and parts of the book consequently read like a travelogue. However, he also includes tables listing the genetic analyses of DNA procured during his tour.He carefully eschews use of the term race in relation to his research, by referring instead to haplogroups passed down intact through the generations. In short, much of his book is devoted to identifying genetic markers that distinguish between European, Asian and American Indian ancestry. Thus, he obtained DNA samples from a number of American born white entertainers, and found John Wayne, Kirk Douglas, Sophia Loren, Grace Kelly, Katherine Hepburn and Spencer Tracy to be of purely European ancestry (p. 306). The DNA of Gregory Peck, by contrast, contained a genetic marker that indicated that one fairly remote ancestor had hailed from Africa. Orson Welles also had evidence of an African ancestor, while Dorothy Lamour's sample revealed traces of both African and Native American origin, although in her case very remote (p. 308- 310).From mitochondrial DNA taken from numerous Native American tribes, six distinct DNA clusters have been identified, each cluster being distinguished from the others by unique mutations. One of the gene clusters, found predominantly in Central and South America, suggests either Polynesian or Southeast Asian ancestry. …