Distribution of Ks values of orthologous pairs for identifying speciation events. Data were grouped into bins of 0.02 Ks units for graphing. The upper right graph shows the Ks distribution of the 6,053 pairs of orthologues identified between P. tabuliformis and P. taeda. Given the rate of substitutions/synonymous site per year, the peaks (Picea glauca = 0.1, P. taeda and P. contort = 0.03, P. pinaster and P. sylvestris < 0.01) indicate the speciation time between P. tabuliformis and these species.
Niu et al. BMC Genomics 2013 14:263 doi:10.1186/1471-2164-14-263