Clustering is the process of finding subsets of
sequences which belong together within a larger set. This is done by
converting discrete similarity scores to boolean links between sequences. That
is, two sequences are considered linked if their similarity exceeds a
threshold. UniGene clustering proceeds in several stages, with each stage
adding less reliable data to the results of the preceding stage. This staged
clustering affords greater control than a more egalitarian treatment of all
links between sequences.