A segment of DNA is isolated and added to a mixture of four deoxynucleotides, two specific oligonucleotide sequences, and heat-stable DNA polymerase. The mixture is then heated to denature the DNA, cooled, and reheated in a number of cycles. Which of the following laboratory techniques does this describe?
(A) Enzyme-linked immunosorbent assay
(B) Gel electrophoresis
(C) Northern blot
(D) Polymerase chain reaction
(E) Sequencing
(F) Southern blot
(G) Western blot