Out of Eden: The Peopling of the World

by Oppenheimer, Stephen

  13. another severe ice age struck: OIS 10, see Lahr and Foley (1998) op. cit. archaic Homo sapiens: on strict cladistic grounds, Homo sapiens sensu lato. To avoid confusion: This is a contentious area; my summary is an oversimplification of the discussions in McBrearty and Brooks op. cit. p. 458; and Foley and Lahr (1997) op. cit. the Middle Palaeolithic: ibid.

  14. given rise to Homo neanderthalensis: Opinion is divided as to whether Homo neanderthalensis evolved in Europe and the Middle East out of this quite recent dispersal, or from an earlier out-of-Africa Homo heidelbergensis movement: see the discussion in Lahr and Foley (1998) op. cit. (but see also discussion in McBrearty and Brooks op. cit. pp. 480–81). Sequencing of Neanderthal mtDNA has suggested a molecular coalescent with modern humans of about 500,000 years ago. (Krings, M. et al. (1999) ‘DNA sequences of the mitochondrial hypervariable region II from the Neanderthal type specimen’ Proceedings of the National Academy of Sciences USA 96: 5581–5.) The coalescent for a particular molecular locus is not necessarily the same as the species (or population) split. The coalescents for other loci, e.g. some of the nuclear polymorphisms within modern humans, go back much further. Even if Homo neanderthalensis and Homo sapiens are regarded as drifted races of Archaic Homo sapiens (sensu lato) (or Homo helmei), their mtDNA coalescent may well go back half a million years (i.e. much earlier than the type specimen for Archaic Homo sapiens) irrespective of precisely when the ancestor of Neanderthals left Africa. and had several possible relatives in India and China: Stringer regards Homo heidelbergensis as the ancestor of modern humans and Neanderthals and tends to place Asian specimens such as Dali, Maba, Narmada, and Zuttiyeh in this group. See Stringer, C. (1996) ‘Current issues in modern human origins’ in W.E. Meikle et al. (eds) Contemporary Issues in Human Evolution (California Academy of Sciences, San Francisco) pp. 115–34.

  15. OIS 6; note that ‘Homo sapiens’ with no other qualifier means anatomically modern Homo sapiens (sensu stricto). For the population fall to 10,000, see Takahata, N. et al. (1995) ‘Divergence time and population size in the lineage leading to modern humans’ Theoretical Population Biology 48: 198–221.

  16. Ruff et al. op. cit.

  17. For a discussion of Baldwinian coevolution, see Deacon, T. (1997) The Symbolic Species (Penguin, London) pp. 322–34.

  18. For evolution of cultural traits, or ‘memes’, see Blackmore, S. (1999) The Meme Machine (Oxford University Press). See also; F. John Odling-Smee et al. (2003) Niche Construction: The Neglected Process in Evolution (Princeton University Press).

  19. Deacon op. cit. pp. 214–16.

  20. Ibid. Chapters 8 and 9.

  21. Ibid. pp. 248–50.

  22. the greatest theoretical ‘social capacity’: Cetaceans have similar brain volumes to humans but have much larger bodies. As an aside, I gather that dogs, with much smaller brains, have a pretty good memory for personal smells. a group size of over 300: See Table 2.10 in Gamble, C. (1999) The Palaeolithic Societies of Europe, Cambridge World Archaeology (Cambridge University Press) p. 54. exchanging material goods: ibid. Chapter 2.

  23. See discussion in ibid. p. 53–55.

  24. See the discussion and interpretation of Köhler’s work in Englefield, R. (1977) Language: Its Origin and Relation to Thought, eds G.S. Wells and D.R. Oppenheimer (Elek Pemberton, London) Chapter 1; and also an update in Wells, G. (1999) The Origin of Language (Rationalist Press Association, London).

  25. The greatest star of this story is Kanzi: Savage-Rumbaugh, E.S. and Lewin, R. (1994) Kanzi: The Ape at the Brink of the Human Mind (John Wiley, New York). Chimps have also been shown to demonstrate: Deacon op. cit., esp. pp. 413–14.

  26. The Condillac view: Englefield op. cit.; Wells op. cit. The full theory sees gesture language: For a lucid, referenced, non-technical, historical review of the evolutionary versus ‘big bang’ theories of language, see ibid.

  27. genetically hard-wired into our brains: Chomsky, N. (1968) Language and Mind (Harcourt, Brace & World, New York). concept originated with Plato: see the discussion in Englefield op. cit. p. 131. Jakob Grimm: Grimm J. (1851) Über den Urschprung der Sprache in L. Spiedel (ed.) (1911) Aus den kleineren Schriften von Jacob Grimm (Berlin) p. 268. Max Müller, ‘Language is our Rubicon . . .’: Müller, F.M. (1891) The Science of Language Vol. I (Longmans, London) p. 490; ‘without speech, no reason . . .’: ibid. Vol. II p. 79.

  28. Clottes, J. et al. (1995) ‘Radiocarbon dates for the Chauvet-Pont-d’Arc cave’ International Newsletter on Rock Art (INORA) 11: 1–2.

  29. a lopsided brain: Steele, J. (1998) ‘Cerebral asymmetry, cognitive laterality, and human evolution’ Current Psychology of Cognition 17: 1202–14. For a less ‘biologically determinist’ view of cranial asymmetry, see Deacon op. cit. pp. 309–15. Homo habilis is thought by some: The argument for Broca’s area in Homo habilis is less convincing since it relies too much on the concept of Broca’s area as a speech organ.

  30. two important speciation events; mutations might be associated with cerebral asymmetry: Crow, T.J. (2000a) ‘Did Homo Sapiens speciate on the Y chromosome?’ Psycoloquy 11(001) (also at http://www.cogsci.soton.ac.uk/cgi/psyc/newpsy?11.001); Crow, T.J. (2000b) ‘Schizophrenia as the price that Homo sapiens pays for language: A resolution of the central paradox in the origin of the species’ Brain Research Reviews 31: 118–29. Crow, T.J. (2002) ‘Sexual Selection, Timing and an X-Y Homologous gene: did Homo sapiens Speciate on the Y Chromosome’ Proceedings of the British Academy 106: 197–216.

  31. imprinted at an early stage: Human language ability, which includes lexical, syntax, symbolic, and syntactic inference and phoneme analysis (as opposed to learning new languages), can be acquired only during a critical period in early childhood when detailed rote learning skills are still rather poor. After this window period, normal acquisition of a first language is severely impaired. a particular part or parts of the brain: In any case, Broca’s and Wernicke’s classical speech centres evolve their critical nature during human development, i.e. they are plastic at first and their function can be taken over to a certain extent by other areas if they are damaged at a very early stage; see Deacon op. cit. pp. 282–8, 307.

  32. Crow (2000a) op. cit.; Klein, R.G. (1995) ‘Anatomy, behavior, and modern human origins’ Journal of World Prehistory 9: 167–98.

  33. humans and chimps were even more closely related: see Table 3 of Sarich, V. (1971) ‘A molecular approach to the question of human origins’ in P. Dolhinow and V. Sarich (eds) Background for Man (Little Brown, Boston) p. 73. split not much more than 5 million years ago: Now estimated as 6.5 million years – see Goodman, M. et al. (1998) ‘Toward a phylogenetic classification of primates based on DNA evidence complemented by fossil evidence’ Molecular Phylogenetics and Evolution 9: 585–98. 6.5 million years is also the age of the chimp–human split obtained by the author (see Figure 0.3) by extrapolating from another calibration approach and using complete mtDNA sequence data (unpublished analysis SJO).

  34. For a personal account see Watson, J.D. (1968) The Double Helix (New York, Atheneum).

  35. This mutation rate applies if one takes the HVS 2 segment of the mtDNA control region normally studied – see methods in Forster, P. et al. (1996) ‘Origin and evolution of Native American mtDNA variation: A reappraisal’ American Journal of Human Genetics 59: 935–45.

  36. Methods in Forster et al., op. cit.; Saillard, J. et al. (2000) ‘mtDNA variation among Greenland Eskimos: The edge of the Beringian expansion’ American Journal of Human Genetics 67: 718–26.

  37. For the consensus nomenclature, see The Y Chromosome Consortium (2002) ‘A nomenclature system for the tree of human Y-chromosomal binary haplogroups’ Genome Research 12: 339–48.

  Chapter 1

  1. reporting a major advance: Newsweek 11 January 1988. Rebecca Cann and colleagues: Cann, R.L. et al. (1987) ‘Mitochondrial DNA and human evolution’ Nature 325: 31–6. clearly of African origin: The Cann tree was better resolved in Vigilant, L. et al. (1991) ‘African populations and the evolu
tion of human mitochondrial DNA’ Science 253: 1503–7; and then again with further improvements on the African phylogeny, suggesting the single Out-of-Africa line, in Watson, E. et al. (1997) ‘Mitochondrial footprints of human expansions in Africa’ American Journal of Human Genetics 61: 691–704.

  2. Watson et al., op. cit.; Richards, M. and Macaulay, V. (2001) ‘The mitochondrial gene tree comes of age’ American Journal of Human Genetics 68: 1315–20.

  3. A number of trees for such sites including autosomal nuclear loci, each with their single branch coming out of Africa, have already been described: see e.g. Tishkoff, S.A. et al. (1996) ‘Global patterns of linkage disequilibrium at the CD4 locus and modern human origins’ Science 271: 1380–97; Alonso, S. and Armour, J.A.L. (2001) ‘A highly variable segment of human subterminal 16p reveals a history of population growth for modern humans outside Africa’ Proceedings of the National Academy of Sciences USA 98: 864–9. See also Wainscoat, J.S. et al. (1986) ‘Evolutionary relationships of human populations from an analysis of nuclear DNA polymorphisms’ Nature 319: 491–3.

  For the Y chromosome, one single mutation on the African tree (M168) defines all non-African lines. See Underhill, P.A. et al. (2000) ‘Y chromosome sequence variation and the history of human populations’, Nature Genetics 26: 358–61. This means that all non-African males inherit their Y chromosome from only one of the three extant African clans. The problem is that one of the three first-generation male clans descending from M168, haplogroup ‘III’ defined by YAP, is found both within and outside Africa, while the two others are both non-African. Peter Underhill regards YAP as having arisen in Africa, while Mike Hammer regards YAP as a re-entrant from Asia to Africa (rather like mtDNA subgroup M1 reentering Ethiopia). I agree with Hammer – see the discussion in Chapters 3 and 4.

  4. Thomas, M.G. et al. (2000). ‘Y chromosomes travelling south: The Cohen modal haplotype and the origins of the Lemba – the “Black Jews of Southern Africa” ’ American Journal of Human Genetics 66: 674–86.

  5. geographic distributions of the branches and twigs: Underhill et al., op. cit.; Richards, M. and Macaulay, V. (2000) ‘Genetic data and colonization of Europe: Genealogies and founders’ in C. Renfrew and K. Boyle (eds) Archaeogenetics: DNA and the Population Prehistory of Europe (MacDonald Institute for Archaeological Research, Cambridge) pp. 139–41. A child’s skeleton in Portugal: Duarte, C. et al. (1999) ‘The early Upper Paleolithic human skeleton from the Abrigo do Lagar Velho (Portugal) and modern human emergence in Iberia’ Proceedings of the National Academy of Sciences USA 96: 7604–9.

  6. For a theoretical discussion see Wall, J.D. (2000) ‘Detecting ancient admixture in humans using sequence polymorphism data’ Genetics 154: 1271–9. For a practical test with negative results see Labuda, D. et al. (2000) ‘Archaic lineages in the history of modern humans’ Genetics 156: 799–808.

  7. published in Nature in 1986: Wainscoat et al., op. cit. The technical objections: Richards and Macaulay (2001) op. cit.

  8. Y chromosome: Underhill et al., op. cit. other genetic markers: See note 3.

  9. Some of the geographic, climatic and mammalian perspectives in this paragraph are loosely drawn from Turner, A. (1999) ‘Assessing earliest human settlement of Eurasia: Late Pliocene dispersions from Africa’ Antiquity 73: 363–70. depended on the glacial cycle: Geoclimatic changes are from Jonathan Adams’ website, http://www.esd.ornl.gov/projects/qen/

  10. Dates reviewed in: McBrearty, S. and Brooks, A.S. (2000) ‘The revolution that wasn’t: A new interpretation of the origin of modern human behavior’ Journal of Human Evolution 39: 453–563, e.g. p. 455.

  11. These dates depend on which approach to dating the first arrival of modern humans in Europe is used – fossil evidence or stone tools; see Chapters 2 and 3. On the former basis, some would put the first Cro-Magnons more recently.

  12. While present evidence points to a dead-end failure of this first exodus, there is another interpretation: while the date of the earliest colonization of Australia keeps moving back, there is always the remote theoretical possibility that the Israel colonization was contemporary with the movement to Australia, but still failed locally.

  13. Vermeersch, P.M. et al. (1998) ‘Middle Palaeolithic burial of a modern human at Taramsa Hill, Egypt’ Antiquity 72: 475–84.

  14. Chicago anthropologist Richard G. Klein: Klein, R.G. (1989) The Human Career: Human Biological and Cultural Origins (Chicago University Press); see the discussion of this and the 1999 edition in Chapter 2. Jonathan Kingdon and first ‘failed’ northern exodus: Kingdon, J. (1993) Self-made Man – and His Undoing (Simon & Schuster, London). Stringer has taken the simplest approach: Stringer, C. (2000) ‘Coasting out of Africa’ Nature 405: 24–7; Stringer, C. and McKie, R. (1996) The African Exodus (Jonathan Cape, London), illustration (map) 48, p. 169; Vermeersch et al., op. cit.

  15. splitting the African continent into isolated human colonies: Lahr, M.M. and Foley, R. (1998) ‘Towards a theory of modern human origins: Geography, demography, and diversity in recent human evolution’ Yearbook of Physical Anthropology 41: 137–76. this north-and-south viewpoint: The multiple migration view reappears in a more recent article that Lahr and Foley co-authored with geneticists: Underhill, P.A. et al. (2001) ‘The phylogeography of Y chromosome binary haplotypes and the origins of modern human populations’, Annals of Human Genetics 65: 43–62.

  16. Kingdon op. cit.

  17. Turner op. cit.

  18. Richards, M. et al. (2000) ‘Tracing European founder lineages in the Near Eastern mtDNA pool’, American Journal of Human Genetics 67: 1251–76; Richards, M, and Macaulay, V. (2000) op. cit.; Kivisild, T. et al. (1999) ‘Deep common ancestry of Indian and western-Eurasian mitochondrial DNA lineages’, Current Biology 9: 1331–4. Most of the discussion below refers to these references (see also Chapter 3 and notes 4–6 in this chapter).

  19. 50,000 years old: Richards et al. (2000) op. cit. the ‘Out-of-Africa Eve’ twig, L3: Richards and Macaulay (2000) op. cit.

  20. U6 . . . North African lines . . . About one-eighth of maternal gene lines . . . This makes it extremely unlikely: Rando, J.C. et al. (1998) ‘Mitochondrial DNA analysis of Northwest African populations reveals genetic exchanges with European, near-Eastern, and sub-Saharan populations’ Annals of Human Genetics 62: 531–50. Asian ‘M’ super-group . . . absent . . . from Europe, the Middle East and North Africa: see e.g. Richards and Macaulay (2000) op. cit.

  21. If we look at the Y chromosome: Underhill et al. (2000, 2001) op. cit. Using markers passed down through both parents: i.e. using nuclear autosomal markers, Tishkoff et al. op. cit.; Alonso and Armour op. cit.; see also Chapters 3 and 4. Note that the first geneticists to argue explicitly for an early southern route were Quintana-Murci, L. et al. (1999) ‘Genetic evidence for an early exit of Homo sapiens sapiens from Africa through eastern Africa’ Nature Genetics 23: 437–41. Their analysis does not directly confront the European issue (which, by default, was regarded as a later northern dispersal) and mainly relates to Asian super-haplogroup M, which they regarded as originating in Ethiopia – as opposed to the Indian origin for M that I argue for.

  22. The age of the L3 cluster in Africa was originally estimated at 77,000 ± 2,400 years: Watson, E. et al. (1997) ‘Mitochondrial footprints of human expansions in Africa’ American Journal of Human Genetics 61: 691–704. This estimate increases with improved resolution of the tree round the L3 node; I have calculated a more up-to-date estimate by using complete sequence data from Ingman et al. (2000) ‘Mitochondrial genome variation and the origin of modern humans’ Nature 408: 708–13 as 83,000 years (unpublished work by the author SJO) which uses in principle, the same dating method with calculation of ‘rho’ by averaging new mutations in daughter types – for methods see Forster, P. et al. (1996) ‘Origin and evolution of Native American mtDNA variation: A reappraisal’ American Journal of Human Genetics 59: 935–45; Saillard, J. et al. (2000) ‘mtDNA variation among Greenland Eskimos: The edge of the Beringian expansion’
American Journal of Human Genetics 67: 718–26). This estimate also shows that both M and N and the African branches of L3 and L1c re-expanded around 70,000 years ago, presumably after the worldwide effects of the great Toba explosion. See also Chapters 2 and 4. The L3 age of 83,000 years has also been independently confirmed in Hill, C. (2003) et al. ‘Mitochondrial DNA variation in the Orang Asli of the Malay Peninsula’ (in press).

  23. Gabunia, L. et al. (2002) ‘Earliest Pleistocene hominid cranial remains from Dmanisi, Republic of Georgia: Taxonomy, geological setting, and age’ Science 288: 1019–25.

  24. Rohling, E.J. et al. (1998) ‘Magnitudes of sea-level lowstands of the past 500,000 years’ Nature 394: 162–5; Fenton, M. et al. (2000) ‘Aplanktonic zones in the Red Sea’ Marine Micropalaeontology 40: 277–94.

  25. Stringer places late, large-brained, South and East Asian Homo erectus specimens such as Dali, Maba, Narmada, and Zuttiyeh in a group with Homo helmei, which would imply at least one additional exit by the southern route between those of Homo erectus and modern humans: see Stringer, C. B. (1996) ‘Current issues in modern human origins’ in W.E. Meikle et al. (eds) Contemporary Issues in Human Evolution (California Academy of Sciences, San Francisco) pp. 115–34. See also Foley, R and Lahr, M.M. (1997) ‘Mode 3 technologies and the evolution of modern humans’, Cambridge Archaeological Journal 7: (1)3–36, Fig 5. The appearance of both Acheulian and Middle Palaeolithic technology in India successively over the same period would effectively have increased the number of exits to four.