Size of the pan-genome versus the number of polymorphic sites. The slope of the fitted line gives the ratio between the rate of acquisition of new genes and the population mutation rate ω/θ = 0.017 ± 0.0017. In the inset, the size of the pan-genome (red dots) and number of polymorphic sites (black dots) as a function of the number of genomes are shown. The lines are least squares fit with a logarithmic law. The error bars represent the standard deviation of the data.
Donati et al. Genome Biology 2010 11:R107 doi:10.1186/gb-2010-11-10-r107