How does an automatic DNA sequencer work?

An automatic DNA sequencer works by using a method called capillary electrophoresis to separate DNA fragments based on their size. The DNA sample is first amplified and tagged with fluorescent dyes, allowing visualization. As the fragments migrate through a capillary tube filled with a gel-like medium, a laser detects the emitted fluorescence from each fragment. The sequencer then records the order of the colored signals, translating them into a sequence of nucleotides (A, T, C, G).