Before revision: In differential display, first all the RNA in each sample is reverse transcribed using a set of 3′ "anchored primers" (having a short sequence of deoxy-thymidine nucleotides at the end) to create a cDNA library for each sample, followed by PCR amplification using arbitrary 5 ′ primers together with anchored 3′ primers identical to those used to create the library; about thirty arbitrary primers can amplify almost all the mRNA.
After revision: In differential display, first all the RNA in each sample is reverse transcribed using a set of 3′ "anchored primers" (having a short sequence of deoxy-thymidine nucleotides at the end) to create a cDNA library for each sample, followed by PCR amplification using arbitrary 3 ′ primers together with anchored 3′ primers identical to those used to create the library; about forty arbitrary primers is the optimal number to transcribe almost all offor cDNA strand amplificationfor RNA strand amplification, the mRNA.