. . "The technique of differential display involves isolation of undegraded MRNA free of genomic DNA. Reverse transcriptase (RT) is necessary forconversion of mRNA to single stranded cDNA by using a two base-anchored oligo-dT primer T12MA, T12MC, T12MG and T12MT where M is a mixture of dA, dC and dG obtained from Beckman Coulter, Calif." . .