II. How Many: A Population or a Pair?
For many years, the discussion of the number of individuals that spawned the modern human race was not accessible to science. Fossils don’t record population sizes, and the antiquity and geography of our ancestors offer little in the way of direct data on the number of individuals alive on the planet at the dawn of Homo sapiens. Only with the advent of modern genetics have scientists been able to more directly explore this question.
However, the raw genetic data say nothing about ancestral population sizes. The evolutionary conclusion that humanity arose from a large population1 rather than a pair of individuals is a consequence of the arbitrary constraints that evolutionists bring to bear on the question. Implicit in the evolutionary claims is the assumption that DNA differences can arise only via the process of copying errors (mutations) that we discussed in the previous section. In other words, under the evolutionary model, the immediate reason why you are genetically different from your parents is that you inherited DNA from each parent. However, according to evolutionary reasoning, the ultimate reason why genetic differences exist at all in the human population is mutations in the distant past.
If you insist on this evolutionary assumption and forbid the consideration of any other hypotheses on the origin of genetic differences, then you are almost forced to conclude that humanity could not have arisen from two people in the last few thousand years. Millions of DNA letter differences exist among humans (about 3–5 million per person on average, which is about 0.1% of the total human DNA sequence),2 and the measured 60 mutations per generation can’t produce this much diversity among humans in just 6,000 years, assuming that mutation rates have always been constant.
However, it doesn’t take much reflection to see that this assumption is shortsighted. Let’s apply it to the YEC model and see how well it works. If we assume, for sake of argument, that mankind did indeed arise from two supernaturally created people (regardless of how long ago it was), and if we further stipulate that genetic differences can arise only via mutations, then we would be forced to conclude that Adam and Eve did not have any genetic differences between them (aside from the X and Y chromosomes, since these are involved in specifying gender).
But this hypothetical scenario leads to some bizarre conclusions. If Adam and Eve decided to fulfill God’s command to be fruitful and multiply, they would have passed on two identical DNA sequences to their offspring. Aside from the few mutations that may have arisen (representing 0.00000001% of the billions of DNA3 letters in our cells — a negligible fraction), Adam and Eve would have basically produced copies of themselves — not slightly modified versions of themselves as we are used to observing in our own children, but identical copies of themselves. Offspring that are completely identical to parents receive a particular label in genetics: clones. Cloning as a means to fulfill the dominion mandate is a strange position to maintain. With all the debate that currently exists over the ethics of human cloning, it is somewhat disturbing to think that God instructed the first man and woman to fill the earth by this process.
A very simple alternative hypothesis resolves the conundrum and also makes straightforward scientific sense: God could have created Adam and Eve with genetic differences from the start (Figure 1). In fact, all of us possess not just 3 billion letters of DNA in our cells. With few exceptions such as red blood cells, the cells of our body possess two versions of our 3 billion letters, which means that each of our cells has 6 billion letters. Each parent passes on only 3 billion in sperm or egg, keeping the total of 6 billion letters constant across generations. Going back in time, Adam would likely have had the same cellular arrangement — two versions of his 3 billion letters — and the same would have been true of Eve.
This arrangement makes sense of the DNA differences that exist in the world today. Before the Fall and after the Fall, the two different copies of Adam and Eve’s DNA would have been reshuffled via at least two processes termed recombination and gene conversion, making each offspring unique and leading to diversity within the human race. After the Fall, mutations (perhaps at a rate of 60 mutations per generation) would have occurred and added to the genetic diversity in their children,4 and leading to the production of diverse offspring (in contrast to cloning). Calculations within the parameters of this model match the worldwide DNA diversity that we observe today.5 Thus, to claim that the millions of DNA differences that separate each person from another somehow invalidates the clear teaching of Scripture about the origin of mankind from two people about 6,000 years ago is scientifically unsupportable. In fact, this type of creation model is considerably more supportive of the genetic paradigm of human diversity than the evolutionary model, as we will show.
The BioLogos website lists at least two other lines of evidence6 in support of their population-not-pair contention, but each of these falls prey to poor logic or unsound science, just like the argument above. One of the claims deals with a subsection of DNA that is repetitive in nature.7 But in attempting to explain the origin and arrangement of these sequences, the BioLogos writers assume human-ape common ancestry. Thus, as an argument against the biblical position that humans were created as a pair and distinct from the apes, it is nothing more than circular reasoning.
The second claim8 deals with the rate at which sections of DNA are swapped during sperm and egg cell production (the technical terms of two swapping processes are genetic recombination and gene conversion), but the conclusions that the BioLogos writers reach is based on erroneous assumptions and outdated science. With respect to the latter, in making their claim, the evolutionists assume only a single process of reshuffling DNA sequences (e.g., recombination) when, in fact, there are at least two (the second and, apparently, much faster process of reshuffling is gene conversion).9 Had they included this faster process in their calculations, they would have discovered that mankind’s genetic history is much shorter than they claimed.10
In summary, just like the evolutionary arguments for human-ape common ancestry, the evolutionary arguments for mankind’s origin from a large population (rather than an original pair) are nothing more than type-3 experiments, which are useless in adjudicating between creation and evolution. There is no scientific evidence that we arose from a group of individuals rather than from Adam and Eve. If evolutionists wish to continue making their claims and be taken seriously, they need to propose a type-1 experiment.
Conversely, by starting with the assumption that God created Adam and Eve with genetic diversity from the start, the YEC model can easily explain the existing genetic diversity among living humans. In fact, the explanatory power of these human DNA findings is so strong that they have led to testable predictions for other species.11
III. When: Ancient or Recent?
As we’ve observed in the preceding section, using DNA sequences to function as a clock is not straightforward. In theory, just like the ticks of a clock mark off the passage of time, the transmission of another 60 DNA mutations from parent to offspring should be able to mark the passage of another generation. However, knowing how much time has passed requires knowing when the clock — whether mechanical or biological — actually started ticking. As we observed above, some (probably most) DNA differences may not represent mutations at all; they may have been supernaturally created in Adam and Eve from the start — e.g., Adam and Eve would have been created with genetic differences. Thus, when we’re evaluating the billions of DNA letters in our cells and trying to determine when the differences began arising, it’s as if we were asked how long a clock has been ticking — but then were told that the clock has at least four hands instead of two.12
Therefore, to use DNA as a clock to measure when humanity began requires a very careful accounting of all potential means of genetic change and all potential genetic starting points. In other words, the only relevant DNA clock to the human origins debate is one in which evolutionists and creationists agree on the mechanism by which DNA differences arise as well as on the number of starting points from which DNA differences can arise.
Only one candidate DNA clock currently fulfills these criteria. Again, the vast majority of the billions of DNA letters in our cells do not lend themselves to a head-to-head comparison. Both sides may claim that the data fits their view, but claiming that the data support a view to the exclusion of the other is very challenging (as illustrated in the previous section).
Conversely, creationists and evolutionists agree on the origin of DNA differences in a tiny subsection of DNA (~16,559 DNA letters long) contained in the energy factories of our cells, called the mitochondria. Mitochondria and mitochondrial DNA (“mtDNA”) are found in both males and females, but only females appear to pass on mtDNA to their offspring. In other words, we each received our mtDNA from our mother, and our spouses received theirs from their mothers. Each of our children in turn did not inherit their father’s mtDNA; they inherited their mother’s.
Evolutionists agree that the current mtDNA differences among modern humans are traceable to a single woman in the past, whom they label “Eve.”13 However, they insist that this woman was part of a population of humans, not a single pair. This conclusion arises, not because of anything inherent to the mtDNA data, but because of the data from the billions of letters in the rest of the DNA sequence and the evolutionary presuppositions that we discussed in the previous section.
From a biblical perspective, all humans trace their ancestry back to Adam and Eve. However, because mtDNA is maternally inherited, YE creationists would agree with evolutionists that mtDNA differences today are traceable to a single woman in the past — Eve (both creation and evolution refer to her with the same name). Furthermore, both evolutionists and creationists would agree that modern mtDNA differences are the result of copying errors (i.e., mutations). Unlike the 3 billion DNA letters of DNA in the cell’s nucleus that come in two versions, mtDNA comes in only one version — effectively, the mother’s version. Hence, mtDNA differences arise via copying errors and were not created in Eve.
Thus, on the question of the origin of mtDNA differences, evolutionists and creationists are in complete agreement, except for one point — when this maternal ancestor lived. (Again, the evolutionary claims about this woman being part of a population have nothing to do with the mtDNA data itself; the population claim is imposed from the outside on top of the mtDNA data.)
To summarize up to this point, when we’re discussing mtDNA, both origins views hold to a single starting point. Because mtDNA comes in one version, not in two versions like the 3 billion letters of nuclear DNA sequence, both origins views also hold to copying errors (mutations) as the sole source of DNA variety (i.e., YE creationists do not believe that God created different mtDNA versions in Eve). Thus, mtDNA comparisons are one of the few type-1 experiments that can actually be performed to answer the question of when humanity began, and since the rate at which mutations occur in mtDNA has already been measured, this experiment can be performed right now.
To use mtDNA as a clock, we simply use this measured mutation rate to make testable predictions based on either the evolutionary timescale or on the YEC timescale and then compare the predictions with the scientific, observed facts. In other words, rather than starting with mtDNA differences in the present and then dialing the clock backward to see how long it would take to get to Eve, we’re going to go backward in time to the beginning under each model and predict what would have happened if the clock were allowed to run forward to the present. Specifically, we will assume for sake of argument that humans originated a long time ago (180,000 years ago under the evolutionary model14) or recently (4,500 years ago under the YEC model,15 representing the end of the Flood — see technical references for technical genetic reasons why the Flood date rather than the creation date was chosen).16 Then we will predict how many mtDNA differences should have accumulated in the timeframe specific to each model, after which we’ll compare these predictions to the actual number of differences in the current human population.
Thus, by multiplying the measured mutation rate of mtDNA17 by 180,000 years or by 4,500 years, we can make testable predictions about the timescale of human origins. Comparing these predictions to actual mtDNA differences at the global scale reveals a result that strongly contradicts the evolutionary timescale and confirms the YEC timescale (Figure 2).18
After 180,000 years, humans would have accumulated over 2,000 DNA differences (range = 1,220 to ~4,700)19 via the process of mutation to mtDNA. In just 4,364 years,20 humans would have accumulated only 30 to 114 mutations.21 Currently, about 78 differences exist on average in African populations (i.e., the most genetically diverse of all the human ethnic groups), with a maximum difference of ~120. Clearly, the YEC timescale accurately predicts the number of DNA differences that we observe today, while the evolutionary timescale predicts numbers an order of magnitude higher. Similar results hold true in animal species, as illustrated in Figure 3.
These findings represent much more than an isolated, irrelevant data point in the bigger creation/evolution debate. As we observed above, mtDNA is one of the only arenas in which a straightforward type-1 experiment can be performed — one of the only arenas in which we can judge the scientific validity of the creation model versus the evolution model. Furthermore, performing this mtDNA experiment in a wide variety of animal species leads to the same conclusion: the biblical view of earth history is correct.22 Thus, the evolutionary timescale runs into trouble not only on the question of human origins but across a much wider swath of biological life.
Implicit in these calculations was the assumption that the mtDNA mutation rate has been constant with time. We made this assumption since it forms the basis for the entire millions-of-years paradigm in the evolutionary model. When evolutionists claim that the earth or the universe are ancient, their methods assume that the geologic or astronomical processes that they observe today have occurred at a constant rate throughout the history of the earth or universe.23
For decades, YE creationists have pointed out the arbitrary nature of this assumption,24 especially in light of the global Flood element of the YEC model of geology.25 Essentially, YE creationists have correctly identified the entire millions-of-years paradigm as nothing more than a type-3 experiment. In short, the evolutionary argument about the age of the earth and of the universe work only if the assumption about constant rates of change is true. Change that assumption and the entire paradigm collapses.
Thus, by assuming constant rates of genetic change in our calculations, we made the calculations overly generous to the evolutionary view. The fact that the evolutionary predictions could not be reconciled with reality even under generous assumptions makes the explanatory dilemma for evolutionists all the greater. If they claim that rates of genetic change were different in the past, they’ve just undermined the foundational assumption of their entire ancient universe/ancient earth view. If they do nothing, they are left with a glaring contradiction between predictions and facts. Hence, these mtDNA results have implications for the evolutionary view far beyond biology, and they make the evolutionary paradigm even harder to maintain in a scientifically consistent and coherent way.
Perhaps the evolutionists will invoke natural selection to explain why their predictions do not match up with facts. In other words, perhaps humans have fewer genetic differences than predicted under the evolutionary model because natural selection eliminated a number of copying errors that arose in the past. This hypothesis would be worth exploring — but only if it leads to testable, falsifiable predictions.
In summary, there is no genetic evidence to support an ancient origin for mankind. The DNA differences in the billions of DNA letters in the cellular compartment termed the nucleus are easily explicable from two people in the last 6,000 years (see previous section), and the mtDNA differences observable today are all the more explicable (Table 4; Figure 2). The mtDNA arena of comparison also happens to be one arena in which a type-1 experiment can be performed, and the evidence strongly contradicts the evolutionary timescale while confirming the YEC timescale. Since these results assumed constant rates of genetic change, and since evolutionary geology and astronomy also depend on the assumption of constant rates of change for their millions- and billions-of-years conclusions, these genetic findings throw into confusion these two fields of physical science as well. Genetically speaking, mankind appears to have originated only a few thousand years ago.
|Cellular compartment||Letters in DNA sequence||Inheritance||Origin of human-human differences under YEC view|
|Nucleus||3,000,000,000||Paternal and Maternal||Majority of DNA differences due to Creation, minority due to mutation|
|Mitochondria||16,559||Maternal||All DNA differences due to mutation|
Again, the success of these initial genetic results gives us confidence that we can predict mtDNA mutation rates for other species, and we are willing to test these predictions in the lab. In fact, we invite our evolutionary colleagues to join us so that we can perform a type-1 experiment as accurately as possible. If our evolutionary colleagues are unwilling or unable to make and test a falsifiable prediction, why should we view their claims as scientific rather than pseudoscientific?
IV. Where: Africa or Ararat?
The mtDNA results discussed above hinted at the one element of human origins that we have not explored in detail — the timing and geography of the origin of African people groups. On the question of geography, creation and evolution are largely in agreement — except for the origin of African people groups. Evolutionists posit that Africans evolved first and then gave rise to the non-African groups.26 In contrast, YE creationists posit the simultaneous origin of the major ethnic groups very soon after the dispersion at the Tower of Babel.
The genetic aspects of the evolutionary claim rests on a technical aspect of mtDNA comparisons. Both evolutionists and creationists use software to visualize the number of DNA differences among various individuals or ethnic groups, and one of the most common visualization tools is the creation of phylogenetic or family trees. Naturally, this implies a genealogical relationship among those connected on the tree, but, in the software employed, ancestry assumptions are not necessary. The tree simply depicts the number of DNA differences in a visually striking way.
When the evolutionists draw trees, they of course assume common ancestry regardless of the species compared, since one of the foundational tenets of evolution is universal common ancestry of all species on earth (i.e., all plants, animals, and humans are descended from a single common and microscopic ancestor). Not surprisingly, when evolutionists draw family trees of the human ethnic groups using mtDNA comparisons, they include chimpanzee DNA.27 This resultant tree — which evolutionists interpret as genealogical relationships — shows some of the African branches splitting off first (about 120,000–180,000 years ago, as we alluded to in section III) followed by non-African groups later (about 50,000 years ago).
Even if you omit the chimpanzee DNA from the comparison and draw the tree using only modern human ethnic groups, it is still obvious that African ethnic groups have about twice as many mtDNA differences among them as do non-African ethnic groups. If you assume that the rate of mtDNA mutations is constant with time, the fact of greater mtDNA diversity in Africans implies that Africans have been around longer than non-Africans.
However, implicit in this conclusion is a technical assumption about the mtDNA mutation rates. To measure these rates empirically, scientists must use pedigrees,28 which means that the units are reported in terms of mutations per generation. To convert these units to absolute time (i.e., mutations per year), scientists must make an assumption about how many years pass per generation. Evolutionists implicitly assume that the generation times (time from birth of parent to birth of child) across all ethnic groups are the same.
However, marriage data from the United Nations suggests that this assumption is not valid (Table 5).29 On average, African females marry earlier in life than non-African females. About 32% of African women are married by ages 15–19 whereas only 12% of non-African women are married by the same age. This roughly three-fold difference disappears at later ages (e.g., about the same number of African and non-African women are married by their 30’s and 40’s), suggesting that the generation time in Africans might be about twice as fast as the generation time in non-Africans. Since mtDNA is passed on maternally, these data imply that some African ethnic groups have twice as many mtDNA differences because twice as many generations have passed in their lineages as compared to non-African lineages.
|Africa: % of women married||32.0||67.4||81.3||83.3||83.6||79.2||74.4||64.7||56.8||44.4||28.2|
|non-Africa: % of women married||11.8||47.2||69.8||77.0||78.2||77.0||73.8||67.7||61.6||51.0||32.2|
The data we presented in figure 2 made predictions for a variety of generation times (e.g., 15 years to 35 years). Under none of these generation times could the evolutionary model correctly predict the amount of DNA differences observable today. In contrast, the YEC predictions correctly predicted the African mtDNA differences under the assumption of a higher generation time (e.g., assuming a generation time of 15 years, the YEC model predicts 69 to 114 DNA differences in 4,364 years, which captures the average mtDNA differences — 78 — present today among Africans). The mtDNA differences among non-Africans (about 49, not displayed in figure 2) were predictable under the YEC model by assuming a generation time of 25 years (predicted range of differences = 41 to 69). Thus, the fact of higher mtDNA diversity in Africans does indeed appear to be due to their earlier age of marriage (and, presumably, of child-bearing), not to their supposed ancient evolutionary origin.
These data notwithstanding, evolutionists have also tried to buttress their out-of-Africa claims with data from the 3 billion DNA letters in the genome of the cell nucleus that we discussed previously — the main engine of heritability and diversity among humans. Specifically, Africans have more DNA differences among these 3 billion letters than non-Africans (only about 1.25-fold more), and they have more combinations of these differences (in technical genetic terms, linkage disequilibrium is lower in Africans).30 To the evolutionist, these facts are consistent with an ancient origin of humans in Africa, and a more recent population bottleneck in their descendants who left Africa to found the modern non-African ethnic groups.
Again, these claims rest on assumptions of identical generation times among African and non-African ethnic groups, an assumption that is not borne out by current data. In addition, it appears that Africans reshuffle (e.g., in technical terms, recombine) their DNA at higher rates and/or in different places than non-Africans, which would explain their extra combinations (e.g., lower linkage disequilibrium) of DNA — a conclusion that even the evolutionary community concedes.31
About the only genetic arena in which evolutionists can still hope to find evidence for an early origin of mankind out of Africa is in the Y chromosome — the chromosome unique to males, which is passed from fathers to sons. Current data indicate that African men have about twice as many Y chromosome differences as non-African men.32 However, the rate at which the Y chromosome changes — either by mutation or by a process termed gene conversion — has not been published for Africans. We predict that African Y chromosomes will change twice as fast as non-African Y chromosomes. Conversely, if evolutionists are confident in their out-of-Africa model of human origins, we invite them to make a counter-prediction — and then test their ideas with us in the lab.
In summary, there is no straightforward genetic evidence for the origin of mankind first in Africa. Evolutionists reach this conclusion genetically by assuming human-ape common ancestry and by assuming that the generation times of all ethnic groups are identical. In the context of the origins debate, the first assumption represents circular reasoning, and the second assumption does not match published data. Africans reproduce earlier than non-Africans and reshuffle their DNA faster/in more places than non-Africans, and both of these facts appear sufficient to explain the data that we observe without invoking separate times of origin for the various people groups in existence today (Table 6).
|Cellular compartment||Inheritance||Genetic differences between Africans and non-Africans||Facts demonstrating contemporaneous origin of African and non- African people groups||Prediction|
|Nucleus||Paternal and Maternal||1.25-fold||Africans reshuffle their DNA faster (promotes retention of DNA differences)|
|Mitochondria||Almost exclusively Maternal||1.5- to 2-fold||As compared to non-African women, twice as many African women marry early (more generations have passed in Africans, leading to more DNA differences)|
|Y chromosome||Paternal||2-fold||Y chromosomes in Africans mutate/undergo gene conversion faster than in non-Africans|