Model fit parameters.

Models described by Haegeman and Weitz [10]. Model A: neutral model with all genes exchanged with environment with parameter θ1. Model C: Genome has a fraction (λ1) of the genome that is rigid (the core), and the rest exchanges genes with the environment with parameter θ1. Model D: Similar to model C except the core exchanges genes with the environment with parameter θ2. The distance from the model fit to the data for B. pseudomallei is given by Δ, with smaller numbers signifying better fit.