Stability measures. Simulations illustrating the relationship between the diameter and genome stability. The simulations start from an ancestor genome of 2000 genes arranged in a circular chromosome. At each step of the simulation one gene is picked at random, moved elsewhere in the genome according to different models and the new chromosome is compared to the ancestor. We simulated different evolutionary models, plotted in different colors: yellow: evolutionary model with random rearrangements; magenta: model with only deletions; black: deletions and graph compression. All other colors correspond to local rearrangements where the new position is sampled from a normal distribution : cyan: ; red: ; Blue ; Green . A) Relationship between the diameter, normalized by the number of core genes, and the number of gene movements after separation from the ancestor chromosome. In this panel, we also show the standard deviation for different simulations (thickness of the series). B) Relationship between backbone stability and normalized diameter. The relationship appears to be the inverse of that in (A) suggesting (C) an almost linear relationship between the number of rearrangements and backbone stability. The relationship of the stability with the number of changes does not contain information about the pattern of gene translocation while the diameter is markedly different for local or global gene movements.