TABLE 7

Maximum-likelihood estimates (MLE) and 90% highest posterior density (HPD) intervals of divergence time estimates for pairwise comparisons between P. amoena, P. cyanea, and P. caerulea

Constant populationbVariable populationcWith migration (initial peak)dWith migration (high point)d
Comparisontt (yr)ett (yr)ett (yr)ett (yr)e
P. cyanea × P. amoena
    MLEa0.2105138,0000.207136,0000.211138,0000.211138,000
    90% HPDa0.0375–0.434525,000–286,0000.037–0.44324,000–291,0000.033–0.44521,700–292,0000.033–0.44521,700–292,000
P. caerulea × P. amoena
    MLEa0.7185486,0000.4825327,0000.1825103,0004.99753,380,000
    90% HPDa0.3555–1.3125241,000–888,0000.2475–1.5325167,000–1,037,000NAfNAfNAfNAf
P. caerulea × P. cyanea
    MLEa0.537363,0000.4935334,0000.073549,7004.99753,380,000
    90% HPDa0.177–1.091120,000–738,0000.1505–1.3265102,000–898,000NAfNAfNAfNAf
  • a MLEs are the locations of the peaks of the posterior probabilities in Figure 4; HPDs are the values along the x-axes in Figure 4 that contain 90% of the area of the histograms.

  • b Divergence time estimates for IM runs under the constant population size model.

  • c Divergence time estimates for IM runs under the variable population-size model, which includes the population splitting parameter s.

  • d Divergence time estimates for IM runs under constant population-size model while allowing for migration. In all comparisons (except P. cyanea × P. amoena) there was an initial peak and a nonconverging, nonzero tail (high point). See Figure 4.

  • e Mutation scaled estimates of divergence time (t) were translated into years using a mutation rate of 3.6 × 10−9 substitutions/site/year (Axelsson et al. 2004).

  • f These runs failed to converge so 90% HPDs are not presented.