Out of Eden: The Peopling of the World

by Oppenheimer, Stephen

  26. between about 12,000 and 20,000 years ago: Dixon, R.M.W. (1997) The Rise and Fall of Languages (Cambridge University Press) p. 94. explain the present diversity of American language families: Nichols uses a particular definition of families defined as ‘stocks’ – see e.g. pp. 24–5 and 233 in Nichols, J. (1992) Linguistic Diversity in Space and Time (University of Chicago Press). English linguist Daniel Nettle: see the discussion on stocks, phylogenetic diversity, and the Americas in Chapter 6 of Nettle, D. (1999) Linguistic Diversity (Oxford University Press).

  27. 167 American language ‘stocks’: Nichols op. cit. These stocks do not exclude the probability of higher-order nodes or groups based on looser rules. Such higher-order groups can be found in other common secondary classifications; clearly, fewer nodes means fewer stocks, and that can more than halve the estimates. a simple function of time: simple = linear, but see also the comment by Nettle op. cit. p. 120.

  28. difficulties with all these analyses: Nettle op. cit. (in his Chapter 6) has criticized Nichols’ methods and suggested an alternative model, again using ‘stocks’. languages per stock varies: Nettle op. cit.

  29. The exception is Australia: It has even been suggested that the present dominant language family in Australia, Pama-Nyungan, was introduced with the dingos – Flood, J. (1995) Archaeology of the Dreamtime (Collins, Australia) pp. 206–8; but see also Dixon op. cit. pp. 89–93. interesting, almost a caricature: These figures are from my own unpublished analysis.

  30. Greenberg, J.H. et al. (1986) ‘The settlement of the Americas: A comparison of the linguistic, dental, and genetic evidence’ Current Anthropology 27: 477–97.

  31. Although I accept that Greenberg’s synthesis of a single Amerind group is difficult to sustain, I shall, for convenience in the genetic discussion below, use the term ‘Amerind’ for Native American languages that are neither Na-Dene nor Inuit-Aleut.

  32. Ward, R.H. et al. (1991) ‘Extensive mitochondrial diversity within a single Amerindian tribe’ Proceedings of the National Academy of Sciences USA 88: 8720–24.

  33. Horai, S. et al. (1993) ‘Peopling of the Americas founded by four major lineages of mitochondrial DNA’ Molecular Biology and Evolution 10: 23–47.

  34. Their early mtDNA results: Wallace, D.C. and Torroni, A. (1992) ‘American Indian prehistory as written in the mitochondrial DNA: A review’ Human Biology 64: 403–16 further clarified the mtDNA types: Torroni, A. et al. (1993a) ‘Asian affinities and continental radiation of the four founding Native American mtDNAs’ American Journal of Human Genetics 53: 563–90; Torroni, A. et al. (1993b) ‘mtDNA variation of aboriginal Siberians reveals distinct genetic affinities with Native Americans’ American Journal of Human Genetics 53: 591–608.

  35. Just one of these clusters, A: Torroni et al. (1993a) op. cit.; the identifying mutations: Torroni et al. (1993b) op. cit.

  36. There were surprising results: In America, A came out at 22,750–45,500 years, B at 6,000–12,000 years, C at 24,000–48,000 years, and D at 13,250–26,500 years – Table 8 in Torroni (1993a) op. cit., p. 584. They suggested a distinct origin for the Na-Dene and Inuit-Aleut: although this could not be definitely inferred from the data.

  37. See also Stariovskaya, Y.B. et al. (1998) ‘mtDNA diversity in Chukchi and Siberian Eskimos: Implications for the genetic history of Ancient Beringia and the peopling of the New World’ American Journal of Human Genetics 63: 1473–91.

  38. Dates vary from 22,000 to 29,000 years ago (e.g. Torroni, A. et al. (1994) ‘A mitochondrial DNA “clock” for the Amerinds and its implications for timing their entry into North America’ Proceedings of the National Academy of Sciences USA 91: 1158–62) to 30,000–40,000 years ago (e.g. Bonatto, S.L. and Salzano, F.M. (1997a) ‘A single and early migration for the peopling of the Americas supported by mitochondrial DNA sequence data’ Proceedings of the National Academy of Sciences USA 94: 1866–971; Bonatto, S.L. and Salzano, F.M. (1997b) ‘Diversity and age of the four major mtDNA haplogroups, and their implications for the peopling of the New World’ American Journal of Human Genetics 61: 1413–23); to expand the horizon to 23–37,000 years ago, see Stone, C.A. and Stoneking, M. (1998) ‘mtDNA analysis of a prehistoric Oneota population: Implications for the peopling of the New World’ American Journal of Human Genetics 62: 1153–70. Although I prefer Forster’s genetic date of entry at 22,000 years, just before the LGM (Forster, P. et al. (1996) ‘Origin and evolution of Native American mtDNA variation: A reappraisal’ American Journal of Human Genetics 59: 935–45), it is clear from these date brackets that Dillehay’s (op. cit.) most controversial earliest dates of Monte Verde occupation 35,000 years ago are not completely ruled out by the genetics.

  39. Initially they had thought: Torroni et al. (1993a,b) op. cit.; It was also soon realized: Forster et al., op. cit.

  40. the three Greenberg groups as a ‘family’: albeit a distant family, since the split was rather deep – Forster et al. op. cit. Neither A1 nor A2 are found in Asia: ibid.

  41. Inuit populations in both North America and Greenland: Saillard, J. et al. (2000) ‘mtDNA variation among Greenland Eskimos: The edge of the Beringian expansion’ American Journal of Human Genetics 67: 718–26. D2 was a feature of Inuit-Aleuts: Forster et al., op. cit. This blossoming D relationship was, however, broken more recently with the discovery that D2 was a more recent introduction from the Siberian side – Stariovskaya et al., op. cit.

  42. Shields, G.F. et al. (1993) ‘mtDNA sequences suggest a recent evolutionary divergence for Beringian and northern North American populations’ American Journal of Human Genetics 53: 549–62.

  43. Forster et al., op. cit. In passing I should mention that geneticists were not the first to point to the importance of Beringia in American ice-age prehistory. Archaeologists such as Knut Fladmark (see below) had been beating this drum for some time.

  44. the Bering Strait was then a land bridge: For a comprehensive chronological map of Beringia, see http://www.ngdc.noaa.gov/paleo/parcs/atlas/beringia/index.html For maps based on bathymetry and the sea-level curve, see Bard, E. et al. (1996) ‘Deglacial sea-level record from Tahiti corals and the timing of global meltwater discharge’ Nature 382: 241–4. The summers were for sure cooler: Schweger, C.E. (1997) ‘Late Quaternary palaeoecology of the Yukon: A review’ in H.V. Danks and J.A. Downes (eds) Insects of the Yukon (Biological Survey of Canada (Terrestrial Arthropods), Ottawa) pp. 59–72. being an Arctic desert at this time: see maps on Jonathan Adams’ ESD ORNL reference website, at http://www.esd.ornl.gov/projects/qen/euras18k.gif and http://www.esd.ornl.gov/projects/qen/euras(2.gif linked to America through their A1/A2 group gene tree: An important piece of support for this scenario was that the deepest A2 founder type was a feature of the Na-Dene and rare-to-absent in the Inuit-Aleut, while the derived A2 types were found throughout Eskimo populations. This meant that A2 most probably originated in the Na-Dene and later diversified in the Inuit-Aleut, including the Siberian Inuit, and spread to their neighbours the Chukchi. In other words, the source of the Beringian A2 founder was from the original American genetic stock on the Alaskan side and not a latecomer from Asia. Saillard et al., op. cit.

  45. Central Americans at 16,000 years: This is likely to be a gross underestimate of human occupation of that region, since 81% of the Central American sample were from the Chibcha culture, known from archaeological evidence to have a time depth of approximately 10,000 years – Torroni et al. (1994) op. cit. a case for the founding lineages . . . arriving before 21,000–22,000 years ago: There is an interesting anomaly in the various ages of B, which was 25,000 years in South America but rather younger, at 19,000 years, in North America. The latter seems to disprove Stariovskaya’s theory (see note 37 above) that B came in after the ice age by a coastal route, but might be still consistent with a re-expansion of B in North America associated with Clovis. the expansion age came out at 11,300 years: Since this date specifically estimated a post-glacial expansion, it hides the real age of the A2 founder type in the ancestors of the Na-Dene a
nd Inuit-Aleut. That age comes out at 25,000 years, which is similar to, in fact rather older than, A2 in Amerinds. In other words, this older date supports the view that the original A1 and A2 ancestors of all three American language groups arose in North America before the last ice age. Saillard et al. (op. cit.) recently reanalysed A2 gene trees and expansion ages among Na-Dene and Inuit-Aleut. Their results give a fascinating account of the continuing cyclical fight against extreme cold climates right down to historical times. They noted first that the Haida Na-Dene inhabiting Queen Charlotte Island off the west coast of Canada must have split from the ancestors of the Inuit-Aleut and the mainland Na-Dene rather early. This was because they share no types with the latter except for the founder A2 root type. For instance, one sub-branch of A2 (16192) originates after this, in Beringia or on the mainland, around 22,000 years ago, subsequently expanding among both Na-Dene and Inuit in the peri-Arctic zone from 6,300 years ago. Another subbranch of A2 (16265G) is much more recent, being found only in Inuit-Aleut and expanding from 3,000 years ago. Saillard et al. trace repeated genetic re-expansions of this Inuit branch to archaeologically proven recolonizations of Greenland over the past few thousand years as mini ice ages waxed and waned. they still owe much of their genetic heritage: Just how much they owe to America is another interesting question explored by Saillard et al. (op. cit.). Stariovskaya et al. (op. cit.) demonstrated that the other Inuit founding lineage, D2 was derived not from the American D1 but from Beringian contact with Siberia. This is the only clear evidence for a late separate entry into the Americas. Clearly this implies that Inuit and Aleuts are to a small extent an admixed American/Siberian population, not simply a new migration. Saillard and colleagues point out that the Siberian D2 input may only be very recent, within the past thousand years or so.

  46. Bonatto and Salzano (1997a, op. cit.) say essentially the same thing about the Beringian refuge and re-expansion, while Stone and Stoneking (op. cit.) and Stariovskaya et al. (op. cit.) have variations on the theme. What differs in all these other reports is that their dates of first entry into the Americas are even earlier than Forster’s, generally in excess of 30,000 years. It is inappropriate to go into the virtues of different methods of genetic dating in this book. As an observer, my own preference is for the method used by Forster and colleagues, i.e. calculation of rho (Forster et al., op. cit.) That is the method I have used for most of the estimates in this book, and is based on calculating the average number of mutations in a gene tree. It has the advantage that it is relatively independent of unknown past variations in population size (which produces more conservative estimates in this case). Whichever method is used, however, the result easily breaks the Clovis-first mould and means that the Americas were most likely colonized before the last ice age.

  47. Argentinian geneticist Graciela Bailliet: Bailliet, G. et al. (1994) ‘Founder mitochondrial haplotypes in Amerindian populations’ American Journal of Human Genetics 55: 27–33. his new method of genetic tree-building: Fig. 7 in Bandelt, H.-J. et al. (1995) ‘Mitochondrial portraits of human populations using median networks’ Genetics 141: 743–53. a European X group: Torroni, A. et al. (1996) ‘Classification of European mtDNAs from an analysis of three European populations’ Genetics 144: 1835–50.

  48. rates of 5 and 11–13 per cent . . .: Brown, M.D. et al. (1998) ‘mtDNA Haplogroup X: An ancient link between Europe/Western Asia and North America?’ American Journal of Human Genetics 63: 1852–61; see also Ward et al., op. cit. rates of 25 per cent: Brown et al., op. cit.

  49. DNA was extracted from remains in the Norris Farms ancient cemetery – Stone and Stoneking op. cit.; also reported and discussed in Brown et al., op. cit.

  50. Chatters, J. (2002) http://www.mnh.si.edu/arctic/html/kennewick_man.html Originally published in Newsletter of the American Anthropological Association, 1996. Also Chatters, J.C. (2000) ‘The recovery and first analysis of an early Holocene human skeleton from Kennewick, Washington’, American Antiquity 65: 291-316.

  51. Letter from Secretary of the Interior Bruce Babbitt to Secretary of the Army Louis Caldera, 21 September 2000, regarding disposition of the Kennewick Human remains; Report on the Non-Destructive Examination, Description, and Analysis of the Human Remains from Columbia Park, Kennewick, Washington, October 1999; Powell, J.F. and Rose, J.C. (1999) Report on the Osteological Assessment of the ‘Kennewick Man’ Skeleton (CENWW.97. Kennewick) Chapter 2 in F.P. McManamon (ed.) Report on the Non-Destructive Examination Description, and Analysis of the Human Remains from Columbia Park, Kennewick, Washington. Washington, D.C.: National Park Service, Department of the Interior. (CENWW.97.Kennewick).

  52. Chatters op. cit.

  53. Chandler, J.M. and Stanford, D. (2001) ‘Immigrants from the other side?’ Mammoth Trumpet (Center for the Study of the First Americans, Department of Anthropology, Texas A&M University) 17(1): 11–16.

  54. Stanford, D. and Bradley, B. (2000) ‘The Solutrean solution: Did some ancient Americans come from Europe?’ Discovering Archaeology (Feb. 2000). See review of this old theory: Holden, C. (1999) ‘Were Spaniards among the First Americans?’ Science 286: 1467–8.

  55. Brown et al., op. cit.

  56. Stone and Stoneking op. cit. p. 1168.

  57. Karafet, T.M. et al. (1999) ‘Ancestral Asian source(s) of New World Y-chromosome founder haplotypes’ American Journal of Human Genetics 64: 817–31; Merriwether, D.A. et al. (1996) ‘mtDNA variation indicates Mongolia may have been the source for the founding population for the New World’ American Journal of Human Genetics 59: 204–12.

  58. Spirit Cave Man, at around 9,400 years: uncorrected radiocarbon date, Barker, P. et al. (2000) ‘Determination of cultural affiliation of ancient human remains from Spirit Cave, Nevada’ Report, Bureau of Land Management, Nevada State Office; Jantz, R. and Owsley, D. (1997) ‘Pathology, taphonomy, and cranial morphometrics of the Spirit Cave mummy’ Nevada Historical Society Quarterly 40: 62–84. Three other atypical Palaeo-Indians: An excellent map showing Palaeo-Indian finds and their dates may be found at: http://www.csasi.org/July2000/Earliest%20Americans.htm (author David Heath).

  59. http://www.antropologiabiologica.mn.ufrj.br/english/luzia/estrela1.htm

  60. rather robust East Asian skulls: e.g. Niah, Wajak, Liujiang, Minatogawa, and Upper Cave (see Chapters 5 and 6, and specifically Brown, P. (1999) ‘The first modern East Asians? Another look at Upper Cave 101, Liujiang and Minatogawa 1’, in K. Omoto (ed.) Interdisciplinary Perspectives on the Origins of the Japanese (International Research Center for Japanese Studies, Kyoto) pp. 105–30. Neves did actually find links: e.g. with Upper Cave 101: Neves, W.A. and Pucciarelli, H.M. (1998) ‘The Zhoukoudien Upper Cave skull 101 as seen from the Americas’ Journal of Human Evolution 34: 219–22; Neves, W.A. et al. (1999) ‘Modern human origins as seen from the peripheries’ Journal of Human Evolution 37: 129–33. See also Fig. 8 in Hanihara, T. (2000) ‘Frontal and facial flatness of major human populations’ American Journal of Physical Anthropology 111: 105–34.

  61. Lahr, M. (1996) The Evolution of Modern Human Diversity: A Study of Cranial Variation (Cambridge University Press).

  62. Powell, J.F. and Neves, W.A. (1999) ‘Craniofacial morphology of the first Americans: Pattern and process in the peopling of the New World’ Yearbook of Physical Anthropology 42: 153–88.

  63. Powell and Neves (ibid.) point out, however, that several other scenarios could lead to the same result.

  64. Underhill, P.A. et al. (2000) ‘Y-chromosome sequence variation and the history of human populations’ Nature Genetics 26: 358–61; see also Fig. 1 and Table 1 in Hammer, M.F. et al. (2001) ‘Hierarchical patterns of global human Y-chromosome diversity’ Molecular Biology and Evolution 18(7): 1189–203. The M45 clade has been reclassified as P (Polo) – The Y Chromosome Consortium (2002) ‘A nomenclature system for the tree of human Y-chromosomal binary haplogroups’ Genome Research 12: 339–48.

  65. still common in North Asia: Hammer haplotype 36, 103/495 = 21%, Hammer et al., op. cit. the main A
merican founder: 69/439 = 15.7% of Native American Y chromosomes – ibid., data combined with those in Underhill et al., op. cit. found in Europe: Eu 20 at 1%, Semino, O. et al. (2000) ‘The genetic legacy of Paleolithic Homo sapiens sapiens in extant Europeans: A Y-chromosome perspective’ Science 290: 1155–9. Lake Baikal region is the homeland: Karafet et al., op. cit. dominant European subgroup . . . is also . . .: Hammer haplotype 37 (Semino haplotype Eu18/Consensus type R1b). Comparison of the observed rate in Native Americans with the rate expected from gene flow from North Asia yields an odds ratio of 4.51, based on Hammer et al., op. cit.; R/Ruslan is the reclassified label of M45/M173 – The Y Chromosome Consortium (2002) op. cit.

  66. a direct branch derivative of the Polo root, Q: Q/Quetzalcoatl refers to a haplogroup defined by M45/M3 – The Y Chromosome Consortium (2002) op. cit. all share the special American Y-chromosome type: Karafet et al., op. cit.; Karafet, T.M. et al. (2001) ‘Paternal population history of East Asia: Sources, patterns, and microevolutionary processes’ American Journal of Human Genetics 69: 615–28. which comes out at 22,000 years ago: Bianchi, N.O. et al. (1998) ‘Characterization of ancestral and derived Y-chromosome haplotypes of New World native populations’ American Journal of Human Genetics 63: 1862–71.

  67. Based on odds-ratio comparisons using data from Hammer et al., op. cit.

  68. an extra mutation, M217: For the marker M217 and its East Asian and American distribution, see Underhill P. A. et al. (2001) ‘Maori origins, Y-chromosome haplotypes and implications for human history in the Pacific’ Human Mutation 17: 271–80. highest frequencies are found nearer the Pacific coast: Karafet et al. (1999) op. cit.

  69. Afontova Gora II on the Yenisei River in southern Siberia (see Chapter 5).

  70. The X line has recently been unambiguously identified: Derenko, M.V. et al. (2001) ‘The presence of mitochondrial Haplogroup X in Altaians from South Siberia’ American Journal of Human Genetics 69: 237–41. But note that a single reported instance like this could still be due to recent European intrusion, since the Siberian haplotypes are not unique root types, but lie on a sub-branch shared with some European haplotypes. The 30,000-year-old link: Brown et al., op. cit.