Figure 5

Data comparison for models with rigid and flexible core genomes (models C and D). Comparison of gene frequency distributions with predictions of two models which assume that a part of a genome is more susceptible to gene transfer. The genomes in model C have a rigid core, i.e., some genes cannot be removed from the genomes. The genomes in model D have a flexible core, i.e., theses core genes can be moved around between genomes, but to a lesser extent than the other genes. Model C has two parameters, whereas model D has three parameters. Black circles: data; yellow line with squares: model C; green line with squares: model D.