Fig 4.

PCR-RFLP analysis of the progeny of isolates ATCC 18188 (+) and ATCC 18187 (−). SNP and insertion/deletion between isolates ATCC 18188 and ATCC 18187 were used to design a PCR-RFLP analysis to detect genetic variation between these two isolates and the potential progeny. An SNP was identified between isolates ATCC 18188 and ATCC 18187 that abolished a single BamHI restriction site in ATCC 18188 (A). Note that for ATCC 18188, digestion results in two distinct bands, while digestion of ATCC 18187 fails to produce any novel fragments. Progeny were scored as either genotype 1 or 2, denoting their relationship to ATCC 18188 or ATCC 18187, respectively (see Table 3). A second SNP identified within a different region abolished an NdeI restriction site in ATCC 18187. However, sequences of the amplified region predicted an additional NdeI restriction site shared by both parents, which accounts for the faint low-molecular-weight band appearing after digestion of ATCC 18187 DNA (B). For panels A and B, parental DNAs representing the amplified region around the SNP prior to and after digestion are indicated by one asterisk and two asterisks, respectively. L, DNA ladder.