when subcloning a gene and inserting it into a vector you normally would use x-gal to locate transformants if x-gal is not available what are the alternatives

<<In addition to X-Gal, several alternative [3-gal sub-
strates with different halide groups on the indolyl rings are commercially available. These can be substituted directly for X-Gal in the staining procedures described here, each generating a characteristic color
and resolution of staining [ 1 l] (Fire and Xu, unpublished). Two derivatives, 5-bromo-3-indolyl-13-D-galactoside ("bluo-gal" [BRL]) and 6-chloro-3-in-
dolyl-13-o-galactoside ("Salmon-gal" [Biosynth AG] or "Red-Gal" [Research Organics]), give more dif
fuse staining than X-Gal. A more useful derivative for detailed histochemistry is 5-bromo-6-chloro-3-indolyl-13-D-galactoside ("Magenta-gal" [Biosynth
AG]), which yields magenta staining with definition comparable to X-Gal. The latter substrate should be
particularly valuable in applications involving localization of two different enzymes (for example, 13-gal
and alkaline phosphatase). >>

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