Demonstration of the selection strategy. (A) Example initial MIRU-VNTR phylogeny constructed for selection of strains for sequencing and analysis. Grey circles represent strains with the phenotype of interest (ph+ strains), the white circles represent strains without the phenotype of interest (ph- strains). The Table with columns L1-5 represent the variable number of tandem repeat at each locus L. (B) Example of selection methodology: For each ph+ strain (grey circle) a neighboring ph- strain is selected such that the distance between the two strains in the phylogeny is minimized. Each control or study strain is only sampled once. The resultant tree of selected strains will consist of matched study and control strains.