The synthesis of complementary DNA (cDNA) from an mRNA template by the action of reverse transcriptase is a fundamental technique in molecular cloning. The objective is to make a large number of long cDNA copies. The quality and length of the cDNA product largely depends on the quality of the mRNA used as the starting material. Great care must therefore be taken to avoid mRNA degradation. The choice of primers and RTase used during the synthesis also influences the final product.
