Printout from an automatic sequencer that uses fluorescent dyes. Each of the four colors represents a different base. The letter N represents a base that cannot be assigned because peaks are too low. Note that, if this were a gel as in Figure 10-17c, each of these peaks would correspond to one of the dark bands on the gel; in other words, these colored peaks represent a different readout of the same sort of data as are produced on a sequencing gel.