The
computer
scans vertically through each
lane of the gel file, and converts the pattern of bands to an
individual
chromatogram with a series of "peaks" corresponding to each of the
bands in the DNA
sequence:
A C G
& T. DNA
migration slows
over the course of the electrophoresis, and multiple bases towards the
end may appear as a single broad band instead of discrete "peaks". This
phenomenon is similar to the compression that occurs at the top of an
autoradiograph. In
this experiment, automatic
base calling is 100% accurate to position 684, and >98% accurate to
the
end of the DNA template at 787 bases. Manual
editing produces effectively 100% accuracy.