In Search of
Our "Biblical Common Ancestor"
by Patrick Young, Ph.D.
Several research papers have been published over the years attempting to justify the evolutionists idea of human / ape common ancestry via DNA comparisons. Perceived genetic bottlenecks have been identified, which report the existence of a single male and female that all humanity originated from. The titles of Adam and Eve have been given to these perceived male and female ancestors perpetuating significant confusion in both the scientific and religious world.
Well-meaning theologians have mistakenly placed deep religious significance on these conclusions while proclaiming the Genesis account has been confirmed. Although some of the genetic comparisons may have religious significance, Christians need to realize that several assumptions in the scientific analyses are distinctly evolutionary and hence unbiblical.
Conversely, evolutionists have claimed the confirmation of mans common ancestry with apes and the establishment of a firm location and timelines. Realistically, a significant amount of the data is subject to conjecture from cladistics, demographic models, and parsimony analysis. Furthermore, several assumptions are made about clock-like mutation rates and the perceived factual nature of human / ape common ancestry.
This discussion will evaluate the scientific methods used to certify these results and determine if the conclusions are justified. Secondly, a religious evaluation of the data will be made so the Christian may comprehend our true ancestral genealogy via the Bible.
In 1987, a group of researchers published a paper reporting their discovery of the common matriarchal ancestor of all living human beings 1. Their theory is based on the use of DNA from the mitochondria to trace all human genetic diversity back to one female, hence the name "Mitochondrial Eve".
Every cell in the body contains tiny organelles called mitochondria (Figure 1). These organelles are sites in which nutrients for the body are broken down to create
energy for eukaryotic cells2. DNA from the mitochondria is especially interesting because it originates from the ovum3, while nuclear DNA (DNA from the nucleus) is a genetic mixture of all four grandparents4.
The lack of genetic mixing in mitochondria anticipates the offspring will receive an almost exact copy of their maternal grandmothers DNA except for some possible mutations. Evolutionists believe these mutations occur at a specified rate and thus may be used to determine the age of the female common ancestor.
Mitochondrial Eve is probably not a real person but a mathematical representation of the woman whose original mitochondrial DNA is present in all humans alive today. The report states she is ~200,000 years old and originated in Africa 5.
Several authors report studying various sequences in the paternally inherited Y-chromosome to determine the common ancestor of all males. Although mitochondrial DNA originates only from the mother, it will be assigned to both the males and females of her offspring. Conversely, Y-chromosomes are only transferred through the patriarchal lineage resulting in a less diverse but equally interesting data set some have called "Genetic Adam" ( or "Y-chromosome Adam").
In 1995, Dorit, et al studied a specific intron of 38 separate men containing 729 base pairs from the Y-chromosome 6. Introns are part of the DNA sequence that do not code for proteins or RNA 7. The function of introns and over 95% of DNA is largely unknown and considered by many evolutionists to be molecular "junk" 8. For this reason, Darwinists believe mutations originating from introns will essentially be neutral and not subject to the concerns of natural selection. However, this assumption is not completely valid since a few current studies suggest both functionality and design in these noncoding sequences 9.
More recent Y-chromosome studies concentrate on a series of noncoding haplotypes to form the genetic marker in the analysis 10,11. Haplotyes are a combination of alleles located on the same chromosome and tend to be inherited together 12. The data in these experiments have more statistical credibility because their characteristic mutations add significant weight to the scientific analysis.
"Genetic Adam" is the male version of "Mitochondrial Eve". It is considered the most recent patriarchal common ancestor and is also a mathematical determination. Dates for "Genetic Adam" have ranged from 35,000 to 100,000 years 13,14 depending on the mutation rate and demographics model used.
The techniques mentioned below were used to determine the existence of both "Genetic Adam" and "Mitochondrial Eve". The primary criteria for the acceptance of these methods by evolutionists are, (1) evolution via common ancestry is fact and (2) humans and apes diverged from a common ancestor about 5 million years ago. Obviously, neither one of these parameters can be rectified with the biblical account of Genesis or Christianity. Furthermore, there are other assumptions made in these methods that are questionable even for an evolutionist. The discussion that follows will focus on the overall validity of these methods to draw such far reaching conclusions about "Mitochondrial Eve" and "Genetic Adam".
Cladistics is a technique in taxonomy designed to reconstruct genealogical relationships based on the idea of common ancestry 15. The methodology proposes that all living creatures may be classified based on a set of perceived primitive or derived characteristics found in modern organisms. One of the most common techniques used to judge the significance of certain cladistic trees is called parsimony. The procedure involves creating cladistic data sets of evolutionary trees and assessing the number of mutational changes in each tree. The most parsimonious tree and hence the most desirable, is the one with the least number of mutations 16.
An example of this type of determination is shown in Figure 2. Cladistic trees are created to describe a specific set of taxa observed. In this example, five sets of
characters describe five different taxa. Tree one demonstrates the minimum number of mutations to explain the distributions and is thus considered most parsimonious.
There are several assumptions in parsimony analysis that can result in significant errors. (1) The tree displaying the least number of mutations is considered the correct evolutionary pathway, which may or may not be true. Moreover, there may be more than one tree with maximum parsimony, but demonstrating a very different mutational pathway 17. Even if the assumption of evolution is valid, it is well known the fossil record demonstrates a muddled pathway that is anything but simple.
(2) If a character trait is shared between two taxa, it is assumed to have been derived from a common ancestor 18. Only if the trait is shown to be shared by two taxa and not a third is homoplasy invoked. Sometimes the researcher believes there is tangible evidence a character could have only evolved once. A weighting factor is then used to minimize the effect of homoplasy in the parsimony analysis. Homoplasy is used liberally by evolutionists to explain observed character traits that cannot be explained by common ancestry.
(3) Occasionally, an assumption is made that character traits in evolution are irreversible and cant revert to the ancestral state 19. Ancestral reversals are another ploy by evolutionists to explain observations that do not fit the common ancestry theory.
The genetic conclusion that the common ancestor for all humans originated from Africa is based on the principle of maximum parsimony. Just how valid is this conclusion? The problem with the data in question is that several other researchers discovered numerous different trees which display maximum parsimony 20. Furthermore, some of these trees do not demonstrate an out of Africa sequence 21. Other researchers have even found trees more parsimonious than the original mitochondrial DNA tree of Cann et al 22. There is also evidence that low level genetic mixing in ancient human populations have confused the DNA such that no conclusion can be made about African origin 23.
The principle of maximum parsimony may provide a viable method to exclude certain evolutionary trees from an experiment, but assuming the simplest tree as correct is not always valid. It is curious the amount of weight this technique has in the biological sciences because it is well documented that evolution (assuming it happens), rarely takes the most efficient route to achieve any type of change.
The idea of homoplasy is a significant problem because there is clear evidence this occurrence is more common than evolutionists care to admit 24. Perceived evolutionary reversals have been observed in the fossil record and assuming they do not exist can result in serious errors. Homoplasy and reversals appear to be used as crutches by the Darwinian community to explain observed characteristics that do not follow evolutionary dogma. Both of these terms mean nothing to a creationist because if you do not believe in evolution, then evolutionary reversals and homoplasy are impossible.
DNA and Mutations
The foundational premise for a mutation rate is the assumption that gene alteration proceeds via clock-like behavior. If this uniformitarian concept is illegitimate, then any conclusion on the age of the common ancestor will be inaccurate. Recently, it has been discovered the mitochondrial DNA clock rate may not be as constant as originally thought25. A condition called heteroplasmy was discovered in the mitochondrial DNA of a known sample set. Heteroplasmy occurs when an offspring will inherit two different mitochondrial DNA sequences from their mother. Although, it was previously thought to be a rare occurrence, heteroplasmy appears to be a frequent event resulting in a significant acceleration of the mutation rate. As an example, the most widely used mutation rate for mitochondrial DNA assumes humans and chimpanzees shared a common ancestor ~5 million years ago 26. This equates to one mutation about every 6000 12,000 years. Recent studies have confirmed the existence of mitochondrial DNA base pair changes resulting in one mutation every 800 years! If this new mutation rate is used on the "Mitochondrial Eve" data, it changes the recent common ancestor from living 200,000 years ago to just 6000 years 27.
The measurement of DNA mutations to resolve human origins gets even stickier. A mystery the molecular evolutionist needs to solve, is how do you know which DNA sequence is the result of random mutations over millions of years and which sequence has remained static. To obtain this answer, one needs to know what the DNA of the original humans looked like before there were any mutations. The creationist would have difficulty answering this question because he would need to analyze the original DNA of the first man. Since Adam is not around, analyzing his DNA is impossible. Evolutionists however, believe that humans and chimpanzees split from a common ancestor ~5 million years ago. So a comparison of human and chimpanzee DNA will identify the sequences to analyze. Therefore, evolutionists can determine the human common ancestor by assuming they already know (or at least are close to) who the common ancestor is. This is called circular reasoning 28.
The investigations are based on population genetics calculations that includes a data set of sequences, an assumed mutation rate, and a model to describe the demographics 29. Placing these parameters in the statistical equation results in a general probability presumably capable of predicting the time to most recent common ancestor 30.
The mutation rate, is thought to be clock-like and calculated with the assumption that all humans, chimps, gorillas, orangutans, etc. diverged from one common ancestor approximately 5 -6 million years ago31,32. The particular gene in question, either the Y-chromosome or mitochondrial DNA sequence is used to determine the specific mutation rate.
The demographics parameter is a model chosen by the researcher to best describe the population in question. The model exists as an attempt to develop a foundational relationship between demographic history and heredity 33. Most models employ assumptions about constant population or exponential population growth. However, these demographic parameters are meaningless unless there is a prior reason to believe the sampled population fits the specified demographic model 34.
The data set is usually obtained from variation studies of a particular gene or chromosome sequence. The strength of the equation is directly dependent on the authority of this data. If there is little variation, the data is weak and conclusions are then based on an assumptive demographic model. The result will be widely varying conclusions depending on the model selection 35-38. The judgments rendered from the "Y-chromosome Adam" data in 1995 strongly suggest this problem 39.
The newer experiments using different haplotypes of the Y-chromosome attempt to rectify the previous problem with improved data. However, mutation rates continue to assume human and primate common ancestry 40 and demographic models are still subject to interpretation. Even the most elaborate population models are insufficient descriptions of human demography. Clearly this limits the range of questions that can be asked and creates unknown biases 41.
The total validity of any statistical conclusion is directly dependent on the quality of data. If mutation rates, sequence data, and demographics are suspect, there should be no surprise a mathematical analysis of common ancestry will yield puzzling conclusions
Our "Biblical Common Ancestor"
The Bible states the first two humans to walk the earth were named Adam and Eve. Adam and Eve had numerous children but only three whose names are explicitly mentioned in the Bible. The book of Josephus actually says Adam and Eve had thirty-three sons and twenty-three daughters 42 .
Their first two males of distinction were named Cain and Abel. Abel was a keeper of sheep, while Cain was a tiller of the ground. Both sons were consistent at bringing the fruits of their labor to the Lord. However, God had more respect for Abels offering because the animal firstfruits were considered of higher quality. This resulted in Cain being resentful of Abel. The Genesis account goes as follows;
"And Cain talked with Abel his brother: and it came to pass, when they were in the field, that Cain rose up against Abel his brother, and slew him". (Gen. 4:8)
After Cain slew Abel, God banished him to the land of Nod where he would be a fugitive and a vagabond.
Eve then gives birth to Adams third son of distinction and named him Seth. Seth becomes the father of the patriarchal lineage whose names are written in the book of Genesis. This complete ancestral genealogy is shown in Figure 3 and proceeds all the way to Noahs three sons, Shem, Ham and Japheth.
Due to the rebellion and unrighteousness of man, God chose to destroy all flesh on the earth except for Noah, his sons and their wives (eight people in all). God commanded Noah to build an ark and design it to house the only humans and animals surviving this great flood.
Since Noah and his sons were the only men surviving the flood, all patriarchal genetic diversity concentrated with Noah. However, the women are more complex. There is no biblical evidence of any sibling or matriarchal relationship among the wives, so their genetic diversity would not intersect at the flood (Figure 4). Although the Bible is silent on this detail, there is not enough evidence to conclude the genetic lineage of women would branch completely back to Eve.
Conversely, it is obvious the female genetic diversity does not bottleneck at the flood.
This brands the matriarchal "biblical common ancestor" conceivably to be Eve and the genetic patriarch as Noah. Some theologians attempt to report our patriarchal lineage extends to Adam and generally, this is correct. However, the global deluge enforced a genetic bottleneck of all male ancestors resulting in a more recent patriarchal lineage than matriarchal.
It is interesting to note some secular researchers have attempted to castigate biblical teaching because their data shows "Genetic Adam" was younger than "Mitochondrial Eve". Furthermore, they state these two mathematical creations probably never met and thus demonstrates the Genesis account is in error 43,44. Armed with the correct understanding of Genesis, the Christian can easily refute this misconception and know the Bible continues to be the foundational truth of God.
"Mitochondrial Eve" was identified from a particular gene sequence and suggested as the first female to carry the code which later spread to all living humans. "Genetic Adam" was identified from the sequencing of a small noncoding region of the Y-chromosome that all males carry. Both of these conclusions originate from mathematical derivations and are probably not actual people. Futhermore, this observed intersect could result from one of many possible genetic "bottlenecks" resulting from a catastrophic event and not the original common ancestor at all.
The 200,000-year age of "Mitochondrial Eve" is skeptical because a constant mutation rate is questionable. Any age of "Genetic Adam" is considered dubious because the data in the original study is the weakest portion of the equation. If the data lacks authority, then the model chosen becomes the basis for interpretation resulting in circular reasoning. Since the most important parameters in their equations are weak, any verdict on age and location is suspicious at best. More recent studies on "Genetic Adam" utilize a more diverse sampling group and have minimized the previous weaknesses in the data set. However, the assumption of a constant mutation rate is still suspicious, so any conclusion on age continues to be suspect.
The conclusion "Mitochondrial Eve" originated from Africa via parsimony analysis is dubious at best. It has been demonstrated that the most parsimonious tree does not necessarily point to Africa. Furthermore, evolution (if it is believed) does not always follow the simplest route which questions any conclusion via parsimony analysis.
Cladistics, mutation rates, parsimony analysis, and demographics parameters for "Mitochondrial Eve" / "Genetic Adam" should be taken with a grain of salt by the creationist. The primary criterion is based on the notion that humans and chimpanzees diverged from a common ancestor millions of years ago. This opinion is unproven and clearly unbiblical.
Evolutionists believe that DNA similarities between humans and chimpanzees are a confirmation of common ancestry. However, similarity (homology) does not confirm common ancestry (evolution). DNA is the information carrier for the development of organisms. If two organisms are morphologically similar, we would expect their DNA to also be similar. It they are not, then the idea that DNA is the informational blueprint for the body plan is in error. This type of similarity is actually strong evidence for an intelligent designer and not evolution via random mutations.
Adam and Eve are considered the parents of all biblical creation, but due to the flood, Noah became the father of all living by virtue of a genetic bottleneck. The science to determine genetic modification verifies mathematical common ancestors for all living men and women today. Scientific information to date also confirms a more recent heredity for the patriarch than matriarch. Both of these conclusions are not in conflict with the Bible but conversely, they should not be considered as a confirmation of the Genesis account either.
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