Table 1.

Demographic parameters and simulation results for the various scenarios presented in this study

ModelsKN*KHrmN§mHColonization timeEstimated interbreeding success**Model A relative probability††
A: Large Neanderthal range2008000.80.10.22200.0051 (0.0033–0.0089)
A′: Restricted Neanderthal range2008000.80.10.22200.0065 (0.0023–0.0107)4.66
A′′: Hybridization in ME only2008000.80.10.2180‡‡0.0153 (0.0048–0.0342)3.74
B: Large K4001,6000.80.10.22200.0037 (0.0013–0.0061)0.86
C: Small K1004000.80.10.22200.0097 (0.0059–0.0150)2.26
C′: Very small K251000.80.10.22400.0302 (0.0239–0.0363)12.8
D: Small m2008000.80.050.12900.0051 (0.0029–0.0092)2.42
E: Small r2008000.40.10.23000.0030 (0.0013–0.0049)1.40
F: Variable KH200200–1,6000.80.10.22200.0054 (0.0033–0.0090)1.21
F′: Variable KH and KN (correlated)50–400200–1,6000.80.10.22200.0049 (0.0021–0.0087)1.22
F′′: Variable KH and KN (uncorrelated)50–400200–1,6000.80.10.22200.0051 (0.0019–0.0089)1.07
G: K fourfold higher in ME200 (50)800 (200)0.80.10.22200.0147 (0.0046–0.0218)5.62
G′: K twofold higher in ME200 (100)800 (400)0.80.10.22200.0072 (0.0052–0.0116)4.72
  • All scenarios were simulated by assuming a deme area of 100 × 100 km2. All scenarios except A′ and A′′ assume that hybridization could occur over the large Neanderthal range shown in Fig. 1. Demographic parameters for scenario A are judged the most plausible, given our review of the literature (Materials and Methods). ME, Middle East.

  • *Neanderthal carrying capacity.

  • Human carrying capacity.

  • Intrinsic rate of growth.

  • §Migration rate between Neanderthal demes.

  • Migration rate between human demes.

  • Approximate time (in generations) for the colonization of Europe from the Middle East as estimated from the simulations. This statistic is determined by the growth and migration rates, and it also varies slightly with the hybridization rate.

  • **Maximum-likelihood estimates of interbreeding success between humans and Neanderthals are reported with limits of a 95% confidence interval within brackets.

  • ††Probability of scenario A relative to the other scenarios computed from weighted AICs (Material and Methods).

  • ‡‡Hybridization occurs for about 80 generations in the Middle East.