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Neandertal mtDNA evidence: reported 1997

Neandertal mtDNA evidence: reported 1997. Dr. Svante Pääbo (Max Planck Institute for Evolutionary Anthropology). mtDNA sequence from type specimen of “ neanderthalensis ” 379 base sequence compared to 994 human lineages 1) mtDNA difference among human lineages: mean of 8 base substitutions

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Neandertal mtDNA evidence: reported 1997

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  1. Neandertal mtDNA evidence: reported 1997 • Dr. Svante Pääbo (Max Planck Institute for Evolutionary Anthropology). • mtDNA sequence from type specimen of “neanderthalensis” • 379 base sequence compared to 994 human lineages • 1) mtDNA difference among human lineages: mean of 8 base substitutions • 2) Mean differences (base-pair substitutions) between Neandertal sequence and • European lineages: 28.2 • African lineages: 27.1 • Asian lineages: 27.7 • North American lineages: 27.4 • Australian/Oceanic lineages: 28.3 • Conclusion?

  2. mtDNA research (2008) • 1) Max Planck Institute for Evolutionary Anthropology + • 2) 454 Life Sciences Corporation • 38,000 ybp Croatian Neandertal • New techniques (< 0.5 g of bone used) • Sequenced > 1 billion mtDNA fragments • Sequences of 3 billion bases obtained • Complete mtDNA has been sequenced (16,000 bp) • Compared to 53 living humans • Modern human and modern humans (2-188 differences) • Modern humans and Neandertals (201-234 differences) • Neandertal mtDNA is not found in modern humans • Evidence for validity of Homo neanderthalensis? • Estimate of divergence date between the two mtDNA lineages: • 660,000 ± 140,000 ybp

  3. Anatomically modern humans

  4. Anatomically modern humans

  5. Intermediacy between H. heidelbergensis and H. sapiens Herto, Ethiopia, Africa 160,000-154,000 ybp (argon-argon dating)

  6. Multiregional model

  7. Out-of-Africa or African Replacement model

  8. Predictions from each model 1. the extinct archaic and extant modern humans in each region will be each other’s closest relatives Lieberman (1995)

  9. Predictions from each model 1. all groups of modern humans will be more closely related to each other than to any archaic species. 2. among archaic species, those from Africa will be the most closely related to modern humans

  10. 53 individuals complete sequence of mtDNA Common ancestor of all modern mtDNAs lived in Africa • Most recent common • ancestor of all modern mtDNA • Most recent common • ancestor of Africans and • non-Africans Consistent with African Replacement Model B A

  11. Comparison of genetic variation (mtDNA) Orange: within group Blue: between groups Chimpanzee subspecies are more genetically variable than any two human populations

  12. Variation in one gene in chromosome 12 among people of 7 geographic regions 12 different alleles • Each plot shows the frequencies of the various alleles for people of a particular region. • Vertical arrangement by travel distance between areas. • If non-African populations were founded by small bands of people migrating out of Africa, then non-African populations should have reduced genetic diversity. • 1. African populations show much greater allelic diversity than non-African populations • 2. Progressive reduction in allelic diversity with distance from Africa. • 3. Consistent with African replacement model.

  13. Paleontological evidence

  14. Competing hypotheses Milford Wolpoff Richard Klein Phillip Rightmire

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