Transformation of variable loci. (A) Positive (black), negative (green), or uncertain (gray) genes at three loci on chromosome 1 for each isolate genome. Strains are grouped by overall genomic similarity based on a report by Keymer et al. (). (B) Growth in M9 with 0.001% amino acids and 0.2% mannose (filled symbols) or (GlcN)2 (open symbols). W6G (blue) lacks genes VC1280 to VC1286. Sa5Y (green) lacks both VC0269 to VC0270 and VC01820 to VC01827. N16961 (orange) encodes all three loci. (C) Isolates Sa5Y (green) and W6G (blue) were grown on crab shell and transformed with gDNA from strain VCXB21. Transformants were selected on LB medium containing the indicated antibiotic or M9 with (GlcN)2 (W6G) or mannose (Sa5Y). (D) Metabolic phenotypes of transformants were confirmed by growth on M9 containing the indicated carbon source. D, gDNA donor strain; R, recipient isolate; T, nine independent transformants. (E and F) The selected locus transformed from the donor strain into the recipient isolate was detected by PCR. M, molecular weight marker (kbp). (E) Probes VC0269 to VC0270 transformed into Sa5Y using primers in VC0268, an intervening gene present in Sa5Y but not in VCXB21, and VC0271. (F) Probes VC1280 to VC1286 transformed into W6G using primers in VC1279, VC1280, and VC1287.