Letter

Modelling the recent common ancestry of all living humans

  • Nature volume 431, pages 562566 (30 September 2004)
  • doi:10.1038/nature02842
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Abstract

If a common ancestor of all living humans is defined as an individual who is a genealogical ancestor of all present-day people, the most recent common ancestor (MRCA) for a randomly mating population would have lived in the very recent past1,2,3. However, the random mating model ignores essential aspects of population substructure, such as the tendency of individuals to choose mates from the same social group, and the relative isolation of geographically separated groups. Here we show that recent common ancestors also emerge from two models incorporating substantial population substructure. One model, designed for simplicity and theoretical insight, yields explicit mathematical results through a probabilistic analysis. A more elaborate second model, designed to capture historical population dynamics in a more realistic way, is analysed computationally through Monte Carlo simulations. These analyses suggest that the genealogies of all living humans overlap in remarkable ways in the recent past. In particular, the MRCA of all present-day humans lived just a few thousand years ago in these models. Moreover, among all individuals living more than just a few thousand years earlier than the MRCA, each present-day human has exactly the same set of genealogical ancestors.

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Acknowledgements

The research of D.L.T.R. was supported by the National Institutes of Health.

Author information

Affiliations

  1. Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

    • Douglas L. T. Rohde
  2. 7609 Sebago Road, Bethesda, Maryland 20817, USA

    • Steve Olson
  3. Department of Statistics, Yale University, New Haven, Connecticut 06520, USA

    • Joseph T. Chang

Authors

  1. Search for Douglas L. T. Rohde in:

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Competing interests

The authors declare that they have no competing financial interests.

Corresponding author

Correspondence to Douglas L. T. Rohde.

Supplementary information

PDF files

  1. 1.

    Supplementary Methods A

    This file contains additional Methods (Further explanation and derivations of mathematical results) and an extra reference.

  2. 2.

    Supplementary Methods B

    This file contains additional Methods (further details of the computational model), Supplementary Figure 1, Supplementary Table 1 and extra references.

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