Pairwise SNP differences between isolates. A: Pairwise SNP difference between all 199 isolates, the peaks represent the pairwise differences between the major lineages. Box indicates subsection shown in B: pairwise SNP differences under 150 SNPs for linked and unlinked pairs. There are many unlinked pairs that have SNP distances which overlap with the distribution of SNP distances for linked pairs.
Bryant et al. BMC Infectious Diseases 2013 13:110 doi:10.1186/1471-2334-13-110