This representation of automated DNA sequencing shows how this technique can be used to detect mutations and other changes in DNA sequence. DNA is amplified in the presence of primers and chain terminators. Either the primers or the terminators are fluorescently labeled, with a different color fluorescence for each base. The automated sequencer uses a laser to excite the DNA containing these fluorescently labeled nucleotides and produces a color-coded intensity profile. In this example, guanine (G) is purple, adenine (A) is green, thymine (T) is red, and cytosine (C) is blue. The sequence can be read from the color of the peaks.
