TABLE 3

Comparison of the mutagenic efficiency of different counterselectable markers

MarkerSelectionaNo. of mutantsbEfficiency (%)
Double-crossover mutantUnexpected mutant
sacBGm, Suc0 (Gms, Sucr)60 (Gmr, Sucr)0
pheS*Gm, Cl-Phe19 (Gms, Cl-Pher)41 (Gmr, Cl-Pher)31.7
  • a Gm, gentamicin; Suc, sucrose; Cl-Phe, p-chloro-phenylalanine.

  • b Sixty colonies were randomly selected to test for resistance (r) or sensitivity (s) to each chemical.