Automated DNA sequencing machine, May 2000.
© Science Museum / Science & Society Picture Library
Automated DNA sequencing machine at the Great Ormond Street Hospital, London. Increasingly, scientists are using machines to help them read DNA code. For automatic analysis, DNA fragments are tagged with fluorescent dyes: a different colour for each DNA letter. The fastest machines pull the different sized fragments through a very fine tube, or capillary. A laser beam then detects the moving, fluorescing DNA fragments as they pas. This is much quicker than manual DNA sequencing.