![Sequencing DNA graph.](http://static.sciencelearn.org.nz/images/images/000/000/955/full/sequencing_dna_large20160310-1429-13oemoz.jpg?1674165207)
Sequencing machines can work out which DNA base is present at each position in a DNA fragment because each one is labelled with a different fluorescent molecule (shown as black, blue, green and red on the graph).
Sequencing machines can work out which DNA base is present at each position in a DNA fragment because each one is labelled with a different fluorescent molecule (shown as black, blue, green and red on the graph).