Additional file 6.

Supplemental Figure S4. Molecular clock estimation of the divergence of the Southeast Asian and Australasian population of B. pseudomallei. As neither the SNP mutation rate nor the number of generations per year are known, we assumed a range of mutation rates from 1.4 × 10-10 in E. coli [78] to 5.2 × 10-10 in Bacillus anthracis [79] and a range of 100 - 300 generations per year as in E. coli [80] to predict that the divergence of these two populations occurred between 16 Ka and 225 Ka (grey box). While actual values for B. pseudomallei may lie outside this range, they would have to differ greatly to support the hypothesis that the two populations diverged before the Australian and Eurasian plates collided. Using these same parameter values, we dated the last common B. pseudomallei ancestor to between 24.9 Ka and 346 Ka (not shown). We also dated the divergence of B. thailandensis and B. pseudomallei to between 307 Ka and 4.27 Ma.

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Pearson et al. BMC Biology 2009 7:78   doi:10.1186/1741-7007-7-78