| abstract |
The invention relates to a method of detecting a differentially expressed gene in a first sample of nucleic acids representing a first population of RNA transcripts and a second sample of nucleic acids representing a second population of RNA transcripts. The nucleic acids in the samples are labled with a member of specific binding pair, and the labeled nucleic acids in each sample are then hybridized to an excess of copies of a gene-specific sequence. The hybridized nucleic acids in each sample are further labeled by binding a second member of the specific binding pair to the first member, in which the second member has an activity to convert a chromogenic substrate into a chromogen. As a result of contacting the second member with the chromogenic substrate, the chromogenic substrate is converted into the chromogen. A difference in the amounts of chromogen produced from assaying the two samples indicate that the gene-specific sequence is differentially expressed in the samples. |