This fascinating book would have been impossible to write prior to the time that the human genome was mapped. That single accomplishment has given rise to various sub-specialties of science, such as evolutionary biology and genetic anthropology, which in turn are helping scientists make connections among disciplines that, taken together, reveal startling truths about we humans, both ancient and modern.
Before the Dawn offers compelling accounts of how we came to be as a species, including the human types who came before us and, tantalizingly, the types who may come after us. At points, this nonfiction book actually becomes a page-turner, such as when Wade discusses the ingenious ways that scientists have learned to trace human DNA back in time to reveal in which parts of the world today’s human populations evolved, as well as the likely migration paths that our ancient forebears took as they spread out from Africa to populate the world.
One of the most interesting sections of the book is the discussion of the ways in which natural selection and a companion evolutionary process called genetic drift have worked together over the millennia to differentiate a quite small “ancestral population” of humans (about 200) into what Wade calls the “five continental races” of the world. He argues convincingly that there really are biological differences among groups of humans, that these differences are adaptations to the environment and that they are directly related to the area of the world to which one’s ancestors migrated when humans originally came out of Africa.
Wade acknowledges that in talking about racial differences among humans he is moving dangerously close to discredited theories of eugenics and he takes pains to explain the science behind the new knowledge he presents. He offers several intriguing examples of these differences, such as the ability of some adults to digest lactose, that are directly linked to the type of environment in which a population evolved.
Bottom line: Before the Dawn is a great read for anyone who is interested in human origins and who wants to know something about the mapping of the human genome, which may be the greatest scientific achievement of our time.