Fig. 1

SNP based phylogram of 634 Salmonella ser. Heidelberg strains from various isolation sources and locations. Phylogenetic tree is arranged in the increasing order of branch length. The entire tree is distributed with a total of 1025 SNP positions. Branches of subtrees in which the major clusters were identified are shown in different colors corresponding to assigned cluster name. Values in bracket indicates the number of SNP positions residing in the corresponding cluster subtree. Cluster names were assigned based on either isolation location category or source country. Node color represents isolation source category of corresponding strain