Branched diagrams showing the relationships among the different alleles of the PE_PGRS16 and PE_PGRS26 genes based on the in-frame deletions, in-frame insertions, frameshifts, and SNPs identified within the two genes' sequences. For each of the observed PE_PGRS16 and PE_PGRS26 alleles, the number and percentage of the 200 clinical M. tuberculosis strains having a given allele are indicated. The length of the lines connecting the observed PE_PGRS alleles represents the number of differing sequence variations between the two alleles. The PE_PGRS16 gene sequence variations are described in Table 2 and the PE_PGRS26 gene sequence variations are described in Table 3.
* This PE_PGRS26 allele shares only the I2 insertion with the S1 I2 allele.