Wednesday, October 1, 2008

Chapter 20 - Population Differences in MtDNA

Things are seldom what they seem; skim milk masquerades as cream."
W.S. Gilbert, “A Many Years Ago,” H.M.S. Pinafore

    Some of the strongest evidence that the afrocentrists are wrong comes from DNA studies of living people across the globe. As explained in Chapter 3, most genes have a number of different alleles. Although all the alleles of a gene are different in their A-C-G-T sequences, several of those alleles may nevertheless code for the same trait (e.g., several different alleles may code for the same eye color).
    Certain alleles are more common in some populations than in others. For example, the allele for blue eyes is common in Europe, but absent in Africa and Asia. 1 As one would expect, scientists have found that particular alleles from different genes tend to group together in different populations. In Europeans, the allele for blue eye color, which is on one gene, is often found with alleles for blond hair, on a different gene. A group of alleles that are inherited together is a “haplotype,” a group of haplotypes is a “haplogroup,” and a group of haplogroups is a “macrohaplogroup.” 2
    There are two mtDNA macrohaplogroups, known as M and N, which include all Eurasians, but very few Africans. The M macrohaplogroup includes people from India 3 and SE Asia and the N macrohaplogroup includes Europeans and northern Asians, as well as (extinct) Cro-Magnons. Figure 20-1 answers the question left over from Footnote 14 in the last chapter, “If Europeans did not come from Africans, why is their mtDNA less varied than Africans?”

Figure 20-1

    In Figure 20-1, time goes from left to right and the number of people alive in Eurasia increases from the bottom to the top, but population size is very approximate. The arrows entering from the left symbolize the many lineages of mtDNA haplogroups that different populations living in Eurasia had prior to the eruption of Mt. Toba and the first ice age. 4 The two population crashes (dips in the curve) were caused by Toba and the two ice ages when large numbers of Eurasians starved to death. Some people in the M and N macrohaplogroups made it through the ice ages, but people in other haplogroups did not, resulting in a population “bottleneck” in the trough of the first ice age (and possibly the second, as well) and leaving the survivors with less variation.
    The “coalescence date,” the date that the populations who have the alleles in the M and N macrohaplogroups began to diverge, has been determined to be about 65,000 ya. 5 The fact that both the M and the N macrohaplogroups are dated near the trough in the first ice age supports the explanation that the M and N coalescence was the result of the extinguishment of most mtDNA haplogroups due to Toba and the first ice age. 6
    When the ice eventually receded, the survivors, who were in a haplogroup within the M or N macrohaplogroups, repopulated Asia and Europe. As the populations expanded, mutations occurred, producing other haplogroups within the M and N macrohaplogroups. 7 The mtDNA of today’s Eurasians has less variation than African mtDNA not because Eurasians are younger than Africans, but because female Eurasians who had mtDNA that was not in the M and N macrohaplogroups did not survive the ice ages. 8
    The ice age bottlenecks that the Eurasians suffered through 9 had very little affect on tropical Africa. 10 Before agriculture (about 12,000 ya), the tropics (African and Asian) supported populations that were much greater (per unit area) than the temperate Eurasian populations, 11 more than enough to account for the higher variations in Africans. Although there was a severe drought in East Africa from 135 to 75 kya, after about 70 kya Africa became much more humid and stable, as shown in Figure 20-2. (Scholz, 2007,).

Figure 20-2

    The African droughts, however, could not be predicted by the Africans (as Fig. 20-2 suggests, they may have been caused by eccentricities in the precession of the earth’s orbit), so they could not be planned for as winters could be in the north, even if the Africans were capable of such planning.
    Figure 20-3 is a wonderful tree 12 that shows the evolution of populations inside and outside the M and N macrohaplogroups.

Figure 20-3

    In the tree, “NG” is New Guinea. Note that all of the Europeans are in the N macrohaplogroup. Note that some of the South Indians, perhaps descended from the Aryans who invaded India, are in proximity to the Southeast Asians, some of the Pacific Islanders, and some of the Australian aborigines. There are several lineages of Australians in the both the M and N macrohaplogroups, suggesting multiple migrations into Australia by widely-separated populations. (Chap. 27).
    No Africans are in either the M or N macrohaplogroup. The lowest branch of Africans (61) is tied directly to the common ancestor with the chimpanzee at the very bottom of the tree; Africans are the race most closely related to chimpanzees and the Nigerians (“Ibo,” “Hausa”) are the closest Africans to chimpanzees. 13 Thus, if OoA is correct, once Africans evolved from an ape into modern humans, they ceased to evolve any further, while Eurasians continued to evolve farther away from those modern Africans and from our ape ancestor. That would explain how Africans can be, at the same time, the most primitive, simian race, yet also the first, and only, race to evolve directly all the way from an ape into a modern human. Section IV, however, presents another explanation that, hopefully, makes more sense.
    Since an individual who is in the M or N macrohaplogroup is modern and those macrohaplogroups originated (coalesced) about 65,000 ya, long after man became modern 160,000 ya, anyone who was in those groups 65,000 ya was modern. Therefore, in order for OoA to be correct, the M and N macrohaplogroups must have originated in Africa where the first modern humans allegedly arose, then were carried out of Africa when those modern Africans left Africa 65,000 ya. If M and N did not originate in Africa, then modern man did not originate in Africa or, at least, only in Africa, and there was no migration of modern man out of Africa into Eurasia, i.e., OoA collapses.
    If M and N originated in Africa, one would expect most of the haplogroups in the M and N macrohaplogroups to be found in Africans, but there are, in fact, almost none, and those that are found in Africans are in NE Africans (e.g., Ethiopia), which is easily accessible from Eurasia. As the fossil skull photos in Chapter 17 (and other evidence to be presented in Chap. 26) show, there were very likely multiple incursions of Eurasians into NE Africa. The small amount of alleles in the haplogroups included within M and N that were found in NE Africans is easily explained as being due to Eurasians crossing over into Africa from the Middle East or from North Africa (the first Egyptians were Caucasian) and interbreeding with Africans.
    Since very few Africans are in macrohaplogroups M and N, it is likely that these macro-haplogroups did not originate in Africa (Chap. 4, Rule 11), but in Eurasia, which means that modern man was in Eurasia at least 65,000 ya. In fact, at least one publication claims that most of the haplogroups, and the oldest ones, in the M macrohaplogroup originated in India, not Africa. “The deep roots [i.e., old age] of M phylogeny [i.e., the evolution of the M macrohaplogroup] clearly establish the antiquity of Indian lineages, especially M2, as compared to Ethiopian [i.e., African] M1 lineage and hence, support an Asian origin of M majorhaplogroup [i.e., macrohaplogroup].” 14 If the M macrohaplogroup originated in India and some NE Africans are in the M macrohaplogroup, then that is evidence that the migration was in to Africa (Section IV), not out of Africa.
    The afrocentrists’ explanation for the absence of Africans in the M and N macrohaplogroups is that any Africans who had M or N alleles “lost” them, i.e., they died without living descendants. But if M and N arose in Africa and the Africans had them, they were very probably beneficial or, at the very least, not harmful, so why would the Africans who had them die out? Africa was little affected by Toba and there were no disasters in Africa that could have wiped out populations in the M and N macro-haplogroups, but left populations in other haplogroups intact. The environment in Africa did not change drastically so as to turn harmless or beneficial alleles in the haplogroups of M and N into deadly liabilities. Rather than say that those alleles were so advantageous in Eurasia that the people having them were able to repopulate those two continents, but so deadly that in Africa that anyone having them died, it is far more likely that no one in Africa had the alleles in M and N until a few Eurasians brought them there.
    Furthermore, why is it only in NE Africa, where Eurasians entered Africa multiple times, that traces of M and N in Africa are found? Under OoA, the fact that different populations fall into different haplogroups is explained as being due to the Founder Effect, where the first migrants from Africa into a new territory all belong to one tribe in the same haplogroup. However, this model is difficult to reconcile with the fact that northeastern Africa harbors all of the African-specific mtDNA lineages. Why, when NE Africa has all the other African-specific mtDNA lineages, did only the Africans who had M and N lineages, the least common lineages in Africa, allegedly leave Africa and replace all the Eurasians? 15
    Also, in going from West Asia to Siberia, haplogroups A, C, D, and G do not gradually merge, but sharply change, even though the land has no sharp dividers, such as water, deserts, or mountains. That is better explained by invasion and conquest than by a gradual expansion of founder populations. (Mishmar, 2003).

Figure 20-4
    Mungo Man (Figure 20-4, a reconstruction) was an “anatomically modern human” fossil found near Lake Mungo, NSW, Australia. (Adcock, 2001). He was buried with his hands interlocked and positioned over his crotch, covered in red ochre.
    MtDNA was recovered from Mungo Man (“LM3”), but it did not match the mtDNA of any living person and differed from modern human mtDNA as much as Neanderthal mtDNA. 16 (That fact establishes that at least some mitochondrial variation has been lost from the Eurasian gene pool, which is consistent with Fig. 20-1.) Since Mungo Man is dated at at least 40,000 ya, 17 his mtDNA is the oldest known mtDNA in the Hss lineage. If every Hss came from Africa, how did the oldest Hss mtDNA get into a modern Australian who lived 40,000 ya? How did modern Africans leave Africa 65,000 ya and arrive in Australia only 25,000 yrs later, and probably sooner, since it is unlikely that Mungo Man was the first person in Australia who had the LM3 mtDNA?
    The LM3 mtDNA found in 40,000 year old Mungo Man is so similar to an “insertion” of nuclear DNA on chromosome 11 that is found in some people living today that scientists have concluded that the nuclear DNA insertion at one time must have been mtDNA. In other words, Mungo Man is descended from an archaic population that had LM3 mtDNA in it and, in one of the individuals in that population, a highly unique event occurred – some LM3 mtDNA migrated into the nucleus in an egg that became a reproducing human. Because that insertion was so unusual, it must have happened to only a single person in that population.
    As the years passed, that individual had descendants, some of whom are the people living today who have that insertion. Other individuals in that same archaic population, who did not have the insertion, also had descendants, 18 some of whom are also still living today alongside those who have the insertion. The insertion is not known to confer any advantage on those who have it, so it was not positively selected, but just gradually spread from that single individual through subsequent populations. Today, over half of the Eurasians have it. 19 Although the size of the archaic population the insertion arose in is not known, it would have had to have been in the thousands in order to be sustaining, so the insertion went from being in only one person in thousands to being in over half of the Eurasians, which would have required hundreds of thousands, if not millions, of years. 20 In other words, the date of the insertion was long before 65,000 ya, the date that supposedly modern Africans supposedly left Africa.
    Mungo Man was Asian and the populations living today in which the majority of people have the insertion are Eurasian, so it is almost certain that the archaic population in which the insertion occurred was Eurasian, not African (Chap. 4, Note 9). And, if that is true, it must also be true that Eurasians did not descend from Africans.
    Because Mungo Man’s LM3 mtDNA is unlike any other known mtDNA, afrocentrists claim that it does not belong to any known macrohaplogroup. However, the mtDNA of most of the people living today who have that ,U.nuclear,/U. LM3 insertion are in the N macrohaplogroup, including the living descendants of the original inhabitants of Australia, e.g., Mungo Man. The only reasonable conclusion is that LM3 is, and always has been, part of the N macrohaplogroup, which is, and always has been, Eurasian.

                            Haplogroup X
    Mitochondrial haplogroups A, B, C, and D are shared by 95% of Native Americans. Haplogroups A, C, and D are found in 58% of the Siberians who migrated into the Americas across the Bering Strait. 21 Haplogroup B is found in people living along the Asian coast who may have come to the Americas later, using boats that followed the coast.
    However, a fifth haplogroup, called X, is 21,6000 ± 6000 yrs old (for the X2 version; Reidla, 2003) and is present in about 20,000 Native Americans living mostly in north central North America; it has also been found in several pre-Columbian populations. Haplogroup X is also present in European populations (Fig. 19-1), but absent in Asians, except people in southern Siberia (Altaia) who are believed to have come from an area just north of Turkey and Iran, i.e. Georgia, where georgicus was found (Chap. 24). This suggests that Europeans brought haplogroup X to the Americas. 22
    There is a variety of other evidence that consistently points to the Europeans as the first Americans. The Na-Dene Indian language (Algonquian) and the Basque language (between Spain and France) are related. The native domesticated America dog did not descend from the N. American wolf, but from the European or Asian wolf.
    Radiocarbon tests of carbonized plant sediments in South Carolina (Topper site) showed that artifacts found in the sediments were at least 50,000 yrs old. (Goodyear, 2004). The artifacts were not the same as more recent (13,000 ya) Clovis artifacts 23 that were made by Asians who crossed the Bering Strait, 24 but were very similar to Solutrean artifacts. (Bradley, 2004). The Solutreans were hunters and craftsmen who lived along the shores of France and Spain at a time of maximum glaciation, when the sea level was about 425 feet lower. 25 Boats of hides and other materials were used, and travel along the northern ice to North America would have been possible. (See migration route in Fig. 19-1). Figure 20-5 shows the skull and a facial reconstruction of 10,630 year old Spirit Cave Man found in Nevada, and Figure 20-6 shows the skull and facial reconstruction of 9300 year old Kennewick Man found in the state of Washington, both of whom are definitely Caucasian. 26

Figure 20-5 Figure 20-6

    How likely is it that “modern” Africans left Africa only 65,000 ya, migrated to what is now France, then traveled across the Atlantic Ocean to what is now South Carolina at least 50,000 ya, when only a few thousand years ago Africans could not even build boats that would take them to islands just off Africa?

No comments: