Dideoxy Sequencing is the enzymatic determination and consideration of DNA or RNA sequence by the rechnique of Sanger and colleagues, based on incorporation of the chain terminating dideoxynucleotides in a growing nucleic acid strand copied by DNA polymerase or the reverse transcriptase from a DNA or RNA template. Different reactions involve dideoxynucleotides containing A, C, G, or the T bases. The reaction products represent the collection of new labeled DNA strands of the varying lengths, all terminating with the dideoxynucleotide at the 3' end (at site of a complementary base in the template nucleic acid), and are separated in the polyacrylamide or urea gel to generate the sequence "ladder". This technique is more commonly used than the "Maxam-Gilbert" (chemical) sequencing.