The "Out of Africa," "African Eve," or "Mitochondrial Eve" theory, proposed in 1987, has captured the popular imagination. Cover stories in magazines gave graphic accounts of this alleged "mother of us all," said to have lived about 200,000 years ago. Since the theory dealt with the origin of modern humans (not the origin of all humans), biochemist Allan Wilson (University of California, Berkeley) was a bit out of line in dubbing her "Eve." However, that historical mistake may have actually enhanced her popularity.
Although the theory was controversial, it was hailed as an important contribution by biochemistry to the understanding of human origins. It now appears that the results of that study were statistically flawed. Newer studies do not rule out an African origin for modern humans, but they do not favor Africa above other parts of the Old World. It further appears that the method utilized is incapable of determining either the date or the geographic location of the first humans.
The theory seemed to be rather brilliantly conceived. It dealt with DNA from energy-producing organelles called mitochondria, which are in the cell but outside the nucleus. This mitochondrial DNA (mtDNA) is inherited only from the mother. The father's mtDNA ends up "on the cutting-room floor." Hence, there is no mixing of male and female mtDNA from generation to generation.
The Berkeley biochemists who developed the theory, Wilson, Rebecca Cann, and Mark Stoneking, made several reasonable but unprovable assumptions. With no mixing from generation to generation, they assumed that all changes in the mtDNA were the result of mutations over time. It was further assumed that these mutations occurred at a constant rate. On the basis of these assumptions, the researchers believed they had access to a "molecular clock." Because mtDNA is thought to mutate faster than other DNA, it is favored because it would lend itself to a more fine-grained index of time.
The original 1987 study involved mtDNA from 136 women from many parts of the world having various racial backgrounds. The analysis led back to a single ancestral mtDNA molecule from a woman living in sub-Saharan Africa about 200,000 years ago. A subsequent and more rigorous 1991 study seemed to confirm and secure the theory.
Unfortunately, there was a serpent stalking this "Eve" as well as the first Eve. The researchers used a computer program designed to reveal a "maximum parsimony" phylogeny. This would be the family tree with the least number of mutational changes, based on the assumption that evolution would have taken the most direct and efficient path—a rather strange assumption, considering the presumed random and haphazard nature of evolutionary change. The computer program was, however, far more complicated than the biochemists realized. They did not know that the result of their single computer run was biased by the order in which the data were entered. It is now recognized that with thousands of computer runs and with the data entered in different random orders, an African origin for modem humans is not preferred over the other continents. There is also the suggestion that in the original study the biochemists were influenced in their interpretation of the computer data by their awareness of other evidence, which seemed to them to favor an African origin.
Henry Gee, on the Editorial Staff of Nature, describes the results of the mtDNA study as "garbage." He states that considering the number of items involved (136 mtDNA sequences), the number of maximally parsimonious trees exceeds one billion. Geneticist Alan Templeton (Washington University) suggests that low-level mixing among early human populations may have scrambled the DNA sequences sufficiently so that the question of the origin of modern humans and a date for "Eve" can never be settled by mtDNA. In a letter to Science, Mark Stoneking (one of the original researchers who is now at Pennsylvania State University) acknowledges that "African Eve" has been invalidated. There is general recognition that Africans have greater genetic diversity, but the significance of that fact remains unclear.
The "African Eve" theory represented the second major attempt by biochemists to contribute to the question of human origins. Earlier, Berkeley biochemist Vincent Sarich estimated that the chimpanzee-human separation took place between five and seven million years ago, based upon molecular studies. Although that date was much later than paleoanthropologists had estimated from fossils, Sarich's date is now almost universally accepted.
In an article written before but published after the recent challenge to "African Eve," Wilson (who died in 1991) and Cann (now at the University of Hawaii, Manoa) laud the virtues of molecular biology in addressing human origins. They state: ". . . living genes must have ancestors, whereas dead fossils may not have descendants." The molecular approach, they claim, ". . . concerns itself with a set of characteristics that is complete and objective." In contrast, the fossil record is spotty. "Fossils cannot, in principle, be interpreted objectively. . . ." They conclude that the method of the paleoanthropologists tends toward circular reasoning. They are right! Creationists have expressed that fact for many years.
However, Wilson and Cann were not able to see the logical fallacy in their molecular biology when it addressed phylogeny. This approach, known as molecular taxonomy, molecular genetics, or the newer related field of molecular archaeology, also traffics in circular reasoning. Molecular genetics, hiding behind the respect we all have for the science of genetics and the objectivity of that science, is highly infused with subjective evolutionary assumptions. In this field, the commitment to evolution is so complete that Wilson and Cann understand "objective evidence" as ". . . evidence that has not been defined, at the outset, by any particular evolutionary model."
The mtDNA study of African Eve, as well as other aspects of molecular genetics, deals with mutations in the DNA nucleotides. Perhaps we could be forgiven for asking: "When an evolutionist looks at human DNA nucleotides, how does he know which ones are the result of mutations and which ones have remained unchanged?" Obviously, to answer that question he must know what the original or ancient sequences were. Since only God is omniscient, how does the evolutionist get the information regarding those sequences which he believes existed millions of years ago? He uses as his guide the DNA of the chimpanzee. In other words, the studies that seek to prove that human DNA evolved from chimp DNA start with the assumption that chimp DNA represents the original condition (or close to it) from which human DNA diverged. That is circularity with a vengeance!
It is also necessary for the evolutionist to determine the rate of mutational changes in the DNA if these mutational changes are to be used as a "molecular clock." Since there is nothing in the nuclear DNA or the mtDNA molecules to indicate how often they mutate, we might also ask how the evolutionist calibrates his "molecular clock." Sarich, one of the pioneers of the molecular-clock concept, began by calculating the mutation rates of various species ". . . whose divergence [evolution] could be reliably dated from fossils." He then applied that calibration to the chimpanzee-human split, dating that split at from five to seven million years ago. Using Sarich's mutation calibrations, Wilson and Cann applied them to their mtDNA studies, comparing ". . . the ratio of mitochondrial DNA divergence among humans to that between humans and chimpanzees." By this method, they arrived at a date of approximately 200,000 years ago for African Eve. Hence, an evolutionary timescale obtained from an evolutionary interpretation of fossils was superimposed upon the DNA molecules. Once again, the circularity is obvious. The alleged evidence for evolution from the DNA molecules is not an independent confirmation of evolution but is, instead, based upon an evolutionary interpretation of fossils as its starting point.
We humans are enamored with our ability to develop sophisticated experiments and to process massive amounts of data. Our problem is that our ability to process data has outstripped our ability to evaluate the quality of the data. Computers are not able to generate "truth" independently, nor can they cleanse and purify data. With the recognition that mtDNA studies are incapable of determining the origin of modern humans, biochemists are now turning to nuclear DNA to help them solve the problem. There are also attempts to recover DNA from Neanderthals and other fossil humans. More and more, molecular genetics and sophisticated computer programs are being enlisted in the service of evolution. The results are advertised as independent confirmations of evolution when in reality they are not. I suspect that molecular techniques are the wave of the future for evolutionary studies. This approach is very convincing, because it appears to be so "scientific" to those who do not recognize the evolutionary presuppositions.
Paleoanthropologists such as Christopher Stringer (British Museum of Natural History) are now claiming that an African origin for modern humans is not dependent upon mtDNA studies alone. The fossils also are said to suggest it. However, an exhaustive survey of the human fossil evidence does not support an African origin for modern humans. In fact, when all of the relevant human fossil material is placed on a time-chart, even according to the evolutionist's dates for those fossils, the results show that humans have not evolved from a primate stock. The fossil evidence against human evolution is so strong as to effectively falsify that theory.
The Bible is God's revelation to those created in His image. Genesis is part of that revelation. God's revelation is more than just the passing on of information. It is the imparting of truth which humans could not know by any other means. The failure of the "African Eve" theory is just another illustration of the impossibility of constructing an authentic record of human origins by scientific means. It is for this very reason that God gave us an authentic revelation of our origins in the book of Genesis.
Henry Gee, "Statistical Cloud over African Eden," Nature, 355 (13 February 1992): 583.
Marcia Barinaga, "'African Eve' Backers Beat a Retreat," Science, 255 (7 February 1992): 687.
S. Blair Hedges, Sudhir Kumar, Koichiro Tamura, and Mark Stoneking, "Human Origins and Analysis of Mitochondrial DNA Sequences," Science, 255 (7 February 1992): 737-739.
Allan C. Wilson and Rebecca L. Cann, "The Recent African Genesis of Humans," Scientific American, April 1992: 68.
Wilson and Cann, 68. Emphasis added.
Marcia Barinaga, "Choosing a Human Family Tree," Science, 255 (7 February 1992): 687.
Wilson and Cann, 68. Bracketed material added.
Wilson and Cann, 72.
- See Marvin L. Lubenow, Bones of Contention (Grand Rapids: Baker Book House, to be published in December 1992). This work is the most extensive treatment of human fossils to be published as yet by a creationist
* Professor of Biblical Studies and Apologetics at Christian Heritage College.