DNA Sequenceing 器品生 12 Automated DNA Sequence anaysis The four dideoxynucleotides used in the sequencing reactions are labeled with different fluor escent dyes which can be distinguished from each other with the help of special filters. This makes it possible to run all four sequencing reactions solh in the same lane on the electrophoresis gel. A laser illuminates the bands as they pass by a window, and their intensities are recor ded on a computer The picture on the right hows the output from one lane of a sequenc ing gel which can hold up to 36 samples.DNA Sequenceing