Figure 1. . Distribution of homozygous and heterozygous variable-number tandem repeats in Mycoplasma pneumoniae.

Homozygous repeats contain only allele with the same repeat copy number in each isolate, which is dominant (52–100%) among all the 13 variable-number tandem repeat loci analyzed, except for 3 loci (Mpn1, P1-AGT and Mpn108a). Heterozygous repeats contain two to ten different alleles with different repeat copy numbers with each isolate (see details in Table 2).