A colorimetric method for DNA hybridization.

A general method has been developed which allows crosslinks to be produced between proteins and single-stranded DNA. Such single-stranded DNA protein complexes have been tested for blot hybridization using two colorimetrically detectable enzymes, namely peroxidase and alkaline phosphatase, as the protein moiety of the probe. After hybridization and incubation with a substrate solution sequences complementary to the probe can be visualized directly without the need of tedious cytochemical sandwich methods. This procedure will detect target sequences, a few kilobases long, in the 1- to 5-pg range.