February 2, 1997
Not About Eve
By JOHN NOBLE WILFORD
The authors argue that Homo sapiens did not evolve in just one place
Race and HUMAN Evolution
By Milford Wolpoff and Rachel Caspari.
Illustrated. 462 pp. New York:
Simon & Schuster. $26.
or ages, confronting the ineffable mystery of their very being, people have conceived of cosmologies to satisfy a hunger to know where they came from. In modern Western societies, the search for origins has taken a scientific turn, often undermining traditional beliefs but leaving many questions unanswered. Indeed, the catechism of paleoanthropology, the study of human origins and evolution, seems in some respects to be a series of questions without firm answers. Nowhere is this provisional quality of knowledge more evident than in the current controversy over the origins of modern humans, the first people anatomically and mentally like us. The dispute centers on two fundamentally different concepts: the out-of-Africa theory versus the multiregional theory.
Simply, one theory holds that modern Homo sapiens is a relatively young species that evolved in one place, Africa. This population then expanded through the world, replacing related species. The other theory posits multiple origins for the human species at different places. Archaic populations originating in Africa migrated to distant regions and there evolved into modern humans separately, though not in total genetic isolation. In this theory lies an explanation for human biological diversity as reflected in what are known as the different races.
Recent research in molecular biology -- finding DNA evidence that the Eve of modern humanity seems to have lived in Africa 100,000 to 200,000 years ago -- lends support to the out-of-Africa hypothesis. But fossils can yield contradictory interpretations. So scientists of equal accomplishment take opposite sides, while others hope some new discovery will resolve the issue.
The authors of ''Race and Human Evolution'' are ardent multiregionalists, and their book is the first comprehensive exposition of that theory for a general audience. Its publication comes none too soon, for multiregionalism has been reduced to the role of foil to the evocative Eve in most popular writing and scientific forums. A recent article in an archeology journal even called the out-of-Africa theory ''effectively the only game in town.''
Milford Wolpoff, a professor of anthropology at the University of Michigan, is an architect (with Alan Thorne of Australia and Wu Xinzhi of China) of the multiregional concept of human origins, and its most provocative defender. His co-author, Rachel Caspari, is a researcher in anthropology at Michigan, and his wife. Their collaboration has produced a spirited book, at times personal and combative, always earnest and thorough. They leave no doubt where they stand: ''We predict we will never find a cradle of modern humanity, because a single source for modern humans does not exist.''
One comes away from the book with many insights into the dynamics of developing, elaborating and defending a scientific thesis -- even the frustration overtaking the authors as they saw multiregionalism being either ignored or misunderstood and thus losing the public battle. ''Eve was glamorous and sexy,'' they concede. ''Eve was a simple theory that made science reporting easy and fun. Eve gave answers and represented 20th-century technology providing answers -- telling us about our origins. Eve implied the brotherhood of all humankind and was politically correct.'' So, as the ''Eve theorists claimed the high moral ground,'' the authors write, multiregionalists were left behind trying to explain a more complex concept and defend it against possible misinterpretation as another example of racist thinking. It was then that they realized ''how thoroughly we had inadvertently grasped the tar baby of racial politics.''
Mr. Wolpoff and Ms. Caspari go to great lengths -- almost half of the book -- to distinguish their theory from the pre-Darwinian concept of polygenism, which at various times served as an intellectual justification for colonialism, slavery and Nazism's master race. Polygenism postulated the separate origins and independent evolution of the races along different, isolated lines. Among its influential exponents were the German scientist Ernst Haeckel in the 19th century, the Harvard anthropologist Earnest Hooton in the early 20th century and, most recently, Carleton Coon, the Harvard-trained author of ''The Origin of Races,'' published in 1962.
POLYGENISM is not to be confused with polycentrism, which the authors call ''the intellectual precursor'' of multiregionalism. In his work with early human fossils from China and Java in the 1930's, Franz Weidenreich, a refugee from Nazi Germany, came to the central realization of polycentrism: races reflect regional variations but are not the product of totally isolated, parallel evolutions, for regional populations never stopped exchanging genes. The chapters of historical background, replete with fascinating accounts of past wars in anthropology, are a book within a book. One sympathizes with the authors' conscientious effort to put distance between their theory and anthropology's racist past, but wishes there had been more streamlining here.
The authors seek to rebut the DNA evidence for a recent origin only in Africa, stressing flaws in data analysis cited by other scientists. They also deal with the seeming paradox at the heart of polycentrism-multiregionalism: how did populations retain regional distinctions and yet evolve together as one species, modern Homo sapiens? Gene flow is the answer. Fossils preserve early traces of regional variations and what is interpreted as a gradual evolution toward modern humans. But a certain amount of gene exchange insured that human evolution followed a common pattern and kept the variations from leading to separate regional species.
One source of misunderstanding about the theory, the authors believe, is its characterization as parallel evolution from a single common base long ago. Instead, they think of races ''as dynamic, changing entities with temporal depth because they are not the diverging branches on an evolutionary bush but the constantly separating and merging channels in a stream.''
How close does this book take us to satisfying answers to the questions of how, when and where modern humans emerged? Supporters of the out-of-Africa theory are not likely to be swayed by the arguments here, but they are put on notice that the debate is far from over.
John Noble Wilford, a senior science writer at The New York Times, regularly writes about human origins.
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