Hierarchical clustering analysis of 34 Salmonella isolates. Flag-based HCA of the 34 Salmonella isolates. To identify the dissimilarity among isolates, only those genes (297) that showed differences in absent and present calls between the isolates were used. The green and red colors indicate absent or present calls, respectively. The isolates with a “Rough” serotype were colored in blue and their specific gene cluster is outlined in blue.