Figure 4.

Plotting of relationships among the sequenced NTHi strains by gene sharing and multi-locus sequence typing. (a) A dendrogram based on genic differences among the 13 strains of H. influenzae. While several pairs of strains appear to be closely related, there is not a well-defined clade structure. The dendrogram was generated using the unweighted pair group method with arithmetic mean (UPGMA) method [44-46]. The number on each branch corresponds to the number of genic differences from the previous branch point. (b) A dendrogram based on sequence alignments of the seven MLST loci. The tree was built using the maximum likelihood method implemented in fastDNAml. The number on each branch corresponds to the number of point mutations per kilobase from the previous branch point. The topologies of the genic and MLST based trees are different. Most notably, strains PittEE and R2846 are closely related in the genic dendrogram, but are separated in the MLST dendrogram. In other instances, such as PittII and R2866, the strains are closely related in both trees.