Practice question

A standard Sanger reaction requires a single-stranded DNA template, a complementary oligonucleotide primer providing a free 3' hydroxyl, DNA polymerase, all four deoxyribonucleotide triphosphates, small amounts of dideoxynucleotide triphosphates, and magnesium-containing buffer. The polymerase extends the primer synthesizing DNA complementary to the template. RNA template is not required because the technique directly sequences DNA; if RNA were the analyte, it must first be converted to cDNA by reverse transcriptase. Therefore DNA polymerase, ddNTPs and primer are indispensable, whereas RNA template is unrelated to core Sanger chemistry.