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Multiregional Evolutionary Theory? |
| Contrary to the claims of a recent study, the multiregional model, which states that modern humans evolved from several different groups of hominids (including Neanderthals) that interbred at some point to produce modern humans, fails to explain the genetics seen in modern humans, Neanderthals, and early modern humans. The biblical model (stating that humans arose from one lineage from a single geographic location) still fits all the data better than the multiregional model. |
Two theories explaining the origin of humans are popular today among evolutionists. The multiregional model states that modern humans evolved from several different groups of hominids (including Neanderthals) that interbred at some point to produce modern humans. The most widely supported theory states that modern humans arose from a single geographic location from one lineage. This theory, although evolutionary in nature, is similar the biblical creation model. The authors of a new study out from "Down Under" (Australia) claim that they have data supporting the multiregional model.
However, previous anatomical studies have cast doubt on the likelihood of Neanderthals being the ancestors of modern humans (1-5). These studies showed differences in Neanderthal's hands (1), the brain case (2), and numerous other features of the Neanderthal skull (3-5). Recent genetic studies comparing the hypervariable (subject to a higher than average mutation rate than usual) region of mtDNA of Neanderthals to that of modern humans, suggest that they were probably a separate species from modern humans (6-8). What has been missing from the previous studies is a comparison of differences between the genetic sequence of living humans compared to ancient, anatomically modern humans.
The first study examining the mtDNA sequences of ancient humans (10 anatomically modern Australians) was published in early 2001 (9). Most of the ancient Australians were dated at less than 10,000 years old. However, one specimen was dated at 62,000 years old, which means that this person lived before the Neanderthals that have already been sequenced. A summary of the mtDNA sequence differences of this individual (compared with the modern human reference sequence, modern Aboriginal humans, Neanderthals, and chimpanzees) can be found in the table, below. The first thing that one notices is that the sequence variation of the ancient Australian compared to modern humans is only 10 base pairs. Previous studies have shown that the average variation among population groups of modern humans is 8 base pairs (the difference between humans and Neanderthals is 26 base pairs, by comparison). The exciting thing for those who believe in the creation model is that the difference between the ancient Australian and Neanderthals included only three shared bases. These results demonstrate that the human genome was already nearly "modern" before Neanderthals died out.
The authors of the study made a big deal about the ancient Australian sequence sharing similarity to a portion of chromosome 11 in modern humans (thought to have been inserted into the human genome from the mtDNA). The authors concluded that the "loss" of the ancient mtDNA variation seen in ancient Australian could explain how Neanderthals do not share mtDNA with modern humans. Although it is certainly possible that part of mtDNA might find its way into the nuclear genome, it doesn't address the issue of how the variation seen in the mtDNA of ancient Australian was "lost." In fact, of the ten sequence differences between the ancient Australian and the modern human reference sequence, five of those bases correspond to natural variations found in modern Aboriginal people, showing that those five bases were not lost at all. This leaves only a five base difference, certainly within the range of variation found among modern humans. The authors' contention that an ancient humans sequence was "lost" is not supported by their data, since the introduction of 5 mutations over a period of 62,000 years is not unreasonable, but would, in fact, be expected in the region of mtDNA that is subject to a high mutation rate. Overall, the lack of "evolution" for humans over the last 60,000 years stands in sharp contrast to the large differences seen between modern humans and Neanderthals over the same period of time.
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A follow-up article on the claims of Adcock et al. appeared in the journal Science in June, 2001.10 In this rebuttal, European evolutionists came to the same conclusions presented here - that the conclusions of Adcock et al. were unwarranted and actually contradicted by the data. They disputed the claim that these ancient anatomically modern humans were genetically separated from modern humans, saying, "These trees show that LM3 and KS8 are well within modern human variation..." These evolutionists came to the same conclusions as myself, as seen in their final comments:
Lastly, even if the problems with both the data and the analysis were ignored, the phylogenetic tree of Adcock et al. would not support the "multiregional model" for modern human origins, because all the modern human sequences are closely related to each other, whereas the Neandertal sequences form an outgroup. Consequently, to see the data of Adcock et al. as a significant problem for the Out of Africa model seems an exaggerated claim.10
Recently, proponents of this theory have claimed that fossils show that an archaic Homo erectus from Java shared key features with living Asians and early modern humans in Australia. Their conclusion was that Asian H. erectus passed on some of its DNA to modern Australians and Asians (Science, 12 January 2001, p. 293). A recent genetic analysis of Asians, however, explodes this theory.11 The study, examining more than 1000 Asian men, determined that all of these men came from one source, between 35,000 and 89,000 years ago. The study is so convincing that some multiregional evolutionists have now dropped this theory. At the annual meeting of physical anthropologists in Kansas City, Missouri, one self-described "dedicated multiregionalist," Vince Sarich of the University of California, Berkeley, admitted:
"I have undergone a conversion--a sort of epiphany. There are no old Y chromosome lineages [in living humans]. There are no old mtDNA lineages. Period. It was a total replacement."