In Sanger’s sequencing method, data used to be collected on a gel. It was read manually.
As an enhancement, in automated dideoxy sequencing method, the data could be interpreted as a computer record. This record is based on light wavelength and intensity; each of the four bases, A,C, T, and G are assigned a specific color. These colors can be obtained in an electropherogram. This data/record is known as “DNA trace”.