population expansion

Browning SR, Browning BL, Daviglus ML, Durazo-Arvizu RA, Schneiderman N, Kaplan RC & Laurie CC 2018 Ancestry-specific recent effective population size in the Americas. PLoS Genet 14:e1007385.

  • we use identity by descent and local ancestry inferred from genome-wide genetic data to estimate overall and ancestry-specific effective population size during the past hundred generations for nine admixed American populations
  • overall effective population sizes dropped substantially in the generations immediately after the commencement of European and African immigration, reaching a minimum around 12 generations ago
  • in modern human populations with low levels of immigration, the overall effective population size tends to be around one-third of the census size, largely because the generation time is approximately one-third of the expected lifespan
  • our pre-admixture model is based on a published model inferred from the 1000 Genomes project data [18]
  • the initial population size (in Africa) was 7310
  • which increased 5920 generations ago to 14474
  • the out of Africa event occurred 2040 generations ago, with the out-of-Africa population size being 1861
  • the Asian and European populations split from the out-of-Africa population 920 generations ago, with sizes of 1032 for Europe and 554 for Asia
  • growth rates of 3.8 × 10−3 for Europe
  • 4.8 × 10−3 for Asia