In DNA sequencing by the Sanger (dideoxy) method:
A) radioactive dideoxy ATP is included in each of four reaction mixtures before enzymatic synthesis of complementary strands.
B) specific enzymes are used to cut the newly synthesized DNA into small pieces, which are then separated by electrophoresis.
C) the dideoxynucleotides must be present at high levels to obtain long stretches of DNA sequence.
D) the role of the dideoxy CTP is to occasionally terminate enzymatic synthesis of DNA where Gs occur in the template strands.
E) the template DNA strand is radioactive.

Question

Quizplus · Accepted Answer

The Sanger (dideoxy) method of DNA sequencing involves the incorporation of dideoxynucleotides (ddNTPs) into a growing DNA strand, which causes termination of the strand at specific points. Dideoxy CTP (ddCTP) terminates synthesis at Gs in the template strand because it is incorporated opposite Gs and lacks the 3' hydroxyl group necessary for the addition of the next nucleotide, effectively ending DNA synthesis at that point.

In DNA Sequencing by the Sanger (Dideoxy) Method