ALIGNMENT-BASED SIMILARITY SCORING METHODS FOR QUANTIFYING THE DIFFERENCES BETWEEN RELATED BIOPOLYMER SEQUENCES

Methods for assigning a quantitative score to the relatedness of aligned polymorphic biopolymer sequences such that small differences between otherwise identical sequences are highlighted are disclosed, including computer systems and program storage devices for carrying out the methods on a computer. Specifically, the methods of the invention comprise the steps of providing a test sequence and a basis set of sequences such that the test sequence and the basis set of sequences are aligned; determining the identity of a monomer unit at a position m in the test sequence; assigning a value of 1 to a local matching probability x.sub.m if the monomer unit at position m in the test sequence matches any members of the basis set at position m, or, assigning a value of between 0 and 1 to a local matching probability x.sub.m if the monomer unit at position m in the test sequence does not match any members of the basis set at position m. In a preferred embodiment, the above method is performed at a plurality of sequence locations and the local matching probabilities are multiplied together to provide a global matching probability.