Figure 2. Genotyping scheme for Mycobacterium leprae determined by using single-nucleotide polymorphisms (SNPs) and variable number tandem repeat (VNTR) polymorphisms, southeastern United States. Shading indicates the base that differentiates SNP type and subtype of M. leprae. The algorithm used for strain typing of M. leprae is based on specific SNP location and type and VNTR copy number at the various locations identified along the chromosome. After identification of the major SNP subtype, M. leprae is further discriminated by using allele numbers at 10 VNTR loci. INS, insertion; DEL, deletion.