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No. 229 "Vital Articles on Science/Creation" July 1992
Institute for Creation Research, PO Box 2667, El Cajon, CA 92021
Voice: (619) 448-0900 FAX: (619) 448-3469 Copyright (c) 1992 by I.C.R.
The Apple (Computer) Bites the African Eve
by Marvin Lubenow*
* Professor of Biblical Studies and Apologetics at Christian
Heritage College.
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 modem 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.(1) 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 modem humans and a
date for "Eve" can never be settled by mtDNA.(2) 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.(3) 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. . . ."(4) 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.(6) 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."(7) 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."(8) 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 modem humans, biochemists are now turning to nuclear DNA to
help them solve the problem. There are also attempts to recover DNA
from Neandertals 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.(9) 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.
References
1. Henry Gee, "Statistical Cloud over African Eden," Nature 355 (13
February 1992): 583.
2. Marcia Barinaga, "'African Eve' Backers Beat a Retreat," Science
255 (7 February 1992): 687.
3. 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.
4. Allan C. Wilson and Rebecca L. Cann, "The Recent African Genesis
of Humans," Scientific American, April 1992: 68.
5. Wilson and Cann, 68. Emphasis added.
6. Marcia Barinaga, "Choosing a Human Family Tree," Science 255 (7
February 1992): 687.
7. Wilson and Cann, 68. Bracketed material added.
8. Wilson and Cann, 72.
9. 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.
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