The output from an automated gene sequencer used by the Human Genome Project to determine the complete human DNA sequence. Each vertical lane shows the sequence of bases in a given stretch of DNA. Each of the 4 different bases is labelled with one of the 4 coloured dyes. The order of the bases is analysed by a computer and assembled to give the continuous base sequence of each chromosome. This image shows the sequence of only a tiny part of one chromosome.Source: The Sanger Centre, Cambridge.