Figure 1.

Location of CDC 684 on the B. anthracis phylogenetic tree. Genotypic analysis of 30 SNPs in ~ 100 isolates from the original Vollum node (Chung, Pearson and Keim, unpublished data) created 10 new collapsed branch points (nodes) along the Vollum sub-lineage (black circles). The positions of 10 new canSNPs are designated by the ancestral to derived SNP type in the Ames Ancestor and A0488 (Vollum) genomes respectively. The CDC 684 isolate creates a new branch (51 SNPs in length) midway along the Vollum branch and shares this node with 15 isolates that were obtained from a collection from the CDC [22].