Practice question

Frederick Sanger developed the dideoxy chain termination method in 1977, revolutionizing DNA sequencing and earning a second Nobel Prize. The method uses DNA polymerase to extend an oligonucleotide primer on a single-stranded template, incorporating normal deoxynucleotides along with small amounts of fluorescently labeled dideoxynucleotides. Random incorporation of a ddNTP terminates elongation because it lacks 3' OH, generating a nested set of fragments whose sizes reveal the sequence after electrophoresis. Gilbert and Maxam developed chemical cleavage sequencing, while Holley contributed to tRNA structure.