Generally, the present invention provides a way of determining in an unsupervised manner additional members for a family that is defined initially through exemplar sequences. The present invention is unsupervised in that it proceeds without any information related to the exemplar sequences defining the family, without aligning the sequences, without prior knowledge of any patterns in the exemplar sequences, and without knowledge of the cardinality or characteristics of any features that may be present in the exemplar sequences. In one aspect of the invention, a method is used to take a set of unaligned sequences and discover several or many patterns common to some or all of the sequences. These patterns can then be used to determine if candidate sequences are members of the family. In another aspect of the invention, a method is used to take a set of sequences and to determine a set of maximal patterns common to a number of sequences. The maximal patterns are determined without any previous knowledge about any properties or features that may be present in the processed sequences.