Fig. 6. The ospC (outer-surface protein C) locus of genomic DNA from B. burgdorferi mouse and tick reisolates as assessed by PCR with primers 7 and 11 (see Table 3). Lane 1, B31-A3 reisolate from mouse joint (infected by needle inoculation); lane 2, ospC7/ospC⁺4 reisolate from mouse joint (infected by needle inoculation); lane 3, ospC7/ospC⁺4 reisolate from mouse joint (infected by tick bite); lane 4, B31-A3 reisolate from larval tick; lane 5, ospC7/ospC⁺4 reisolate from larval tick; lane 6, B31-A3 DNA; lane 7, ospC7/ospC⁺4 DNA; lane 8, ospC7 DNA; lane 9, denatured ospC7/ospC⁺4 PCR product; and lane 10, denatured ospC7 PCR product. Arrows on the right indicate the size of WT ospC and ospC::flaB_P-kan. The doublet present with ospC7/ospC⁺4 DNA reflects both double-stranded and single-stranded forms of the ospC7 PCR fragment, as confirmed by denaturation of the samples prior to running on the gel (lanes 9 and 10). Migration positions of DNA standards are indicated on the left.