The technique of Sanger sequencing takes advantage of the fact that dideoxynucleotides (nucleotides in which the 3' hydroxyl group is absent) act as:
A)palindromic sites.
B)restriction sites.
C)chain terminators.
D)probes.
E)None of the other answer options is correct.

Question

Quizplus · Accepted Answer

Sanger sequencing involves sequencing DNA fragments by copying them in the presence of both normal nucleotides and dideoxynucleotides (ddNTPs). These ddNTPs lack a 3' hydroxyl group, which is necessary for the formation of the phosphodiester bond that links nucleotides together during DNA synthesis. Therefore, when a ddNTP is incorporated into a growing DNA strand, it terminates further elongation. By including a mixture of normal and ddNTPs, a set of fragments of varying length will be generated, each terminating at a specific nucleotide position defined by the type of ddNTP incorporated. Separate sequencing reactions are run for each of the four nucleotides, and the resulting fragments are separated by size using gel electrophoresis, generating a pattern that can be read as the DNA sequence. Therefore, the ddNTPs in Sanger sequencing act as chain terminators.

The Technique of Sanger Sequencing Takes Advantage of the Fact