GENETIC EVIDENCE FOR A PLEISTOCENE POPULATION EXPLOSION

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Abstract
Expansions of population size leave characteristic signatures in mitochondrial “mismatch distributions.” Consequently, these distributions can inform us about the history of changes in population size. Here, I study a simple model of population history that assumes that, t generations before the present, a population grows (or shrinks) suddenly from female size N0 to female size N1. Although this model is simple, it often provides an accurate description of data generated by complex population histories. I develop statistical methods that estimate θ0 = 2uN0, θ1 = 2uN1, and τ = 2ut (where u is the mutation rate), and place a confidence region around these estimates. These estimators are well behaved, and insensitive to simplifying assumptions. Finally, I apply these methods to published mitochondrial data, and infer that a major expansion of the human population occurred during the late Pleistocene.
Funding Information
  • U.S. Department of Health and Human Services (MGN 1 R29 GM39593)
  • National Science Foundation (DBS‐92l1255, DBS‐9310105)