Polymorphism detection utilizing clustering analysis

Abstract

Systems and methods for detecting differences in sample polymers, such as nucleic acid sequences, are provided. Hybridization affinity information for the sample polymers is clustered so that the differences, if any, between or among the sample polymers can be readily identified. By clustering the hybridization affinity information of the sample polymers, differences in the sample polymers can be accurately achieved even in the presence of random and systematic errors.

What is claimed is:  
     
         1 . A method of detecting differences in sample polymers, comprising: 
 inputting a plurality of sets of hybridization affinity information, each set of hybridization affinity information including hybridization affinities between a sample polymer and polymer probes;    clustering the plurality of sets of hybridization affinity information into a plurality of clusters such that all sets of hybridization affinity information in each cluster are more similar to each other than to the sets of hybridization affinity information in another cluster; and    analyzing the plurality of clusters to detect if there are differences in the sample polymers.    
     
     
         2 . The method of  claim 1 , wherein the clustering the plurality of sets of hybridization affinity information includes calculating mean linkage clustering of the clusters.  
     
     
         3 . The method of  claim 2 , wherein the mean linkage clustering of the probes utilizes a distance metric for differences between clusters.  
     
     
         4 . The method of  claim 3 , wherein the distance metric is a Euclidean distance or a city-block distance.  
     
     
         5 . The method of  claim 1 , further comprising displaying a tree structure of the plurality of clusters.  
     
     
         6 . The method of  claim 5 , wherein the distance between the clusters varies with the similarity of the clusters.  
     
     
         7 . The method of  claim 1 , wherein the sample polymers include nucleic acids, amino acids or saccharides.  
     
     
         8 . A computer program product that detects differences in sample polymers, comprising: 
 computer code that receives a plurality of sets of hybridization affinity information, each set of hybridization affinity information including hybridization affinities between a sample polymer and polymer probes;    computer code that clusters the plurality of sets of hybridization affinity information into a plurality of clusters such that all sets of hybridization affinity information in each cluster are more similar to each other than to the sets of hybridization affinity information in another cluster;    computer code that analyzes the plurality of clusters to detect if there are differences in the sample polymers; and    a computer readable medium that stores the computer codes.    
     
     
         9 . The computer program product of  claim 8 , wherein the computer readable medium is selected from the group consisting of floppy disk, tape, flash memory, system memory, hard drive, and a data signal embodied in a carrier wave.  
     
     
         10 . A method of detecting polymorphisms in sample nucleic acid sequences, comprising: 
 inputting a plurality of sets of hybridization affinity information, each set of hybridization affinity information including hybridization affinities between a sample nucleic acid sequence and nucleic acid probes;    hierarchically clustering the plurality of sets of hybridization affinity information into a plurality of clusters such that all sets of hybridization affinity information in each cluster are more similar to each other than to the sets of hybridization affinity information in another cluster; and    analyzing the plurality of clusters to detect if there are polymorphisms in the sample polymers.    
     
     
         11 . The method of  claim 10 , wherein the sample nucleic acid sequence and nucleic acid probes include both sense and anti-sense strands.  
     
     
         12 . The method of  claim 11 , wherein the hybridization affinity information includes four hybridization affinities for the sense strands and four hybridization affinities for the anti-sense strands.  
     
     
         13 . The method of  claim 12 , wherein the four hybridization affinities for the sense strands represent hybridization affinities between nucleic acid probes that differ by at least a nucleic acid at an interrogation position.  
     
     
         14 . The method of  claim 12 , wherein the four hybridization affinities for the anti-sense strands represent hybridization affinities between nucleic acid probes that differ by at least a nucleic acid at an interrogation position.  
     
     
         15 . The method of  claim 10 , wherein the polymorphisms include mutations, deletions and insertions at an interrogation position.  
     
     
         16 . The method of  claim 10 , further comprising normalizing the hybridization affinity information for each set.  
     
     
         17 . The method of  claim 16 , wherein the normalizing the hybridization affinity information for each set includes subtracting an average hybridization affinity from the hybridization affinities and dividing each hybridization affinity by a square root of the sum of squares of the hybridization affinities.  
     
     
         18 . The method of  claim 10 , wherein the clustering the plurality of sets of hybridization affinity information includes calculating mean linkage clustering of the clusters.  
     
     
         19 . The method of  claim 18 , wherein the mean linkage clustering of the probes utilizes a distance metric for differences between clusters.  
     
     
         20 . The method of  claim 19 , wherein the distance metric is a Euclidean distance or a city-block distance.  
     
     
         21 . The method of  claim 10 , further comprising displaying a tree structure of the plurality of clusters.  
     
     
         22 . The method of  claim 21 , wherein the distance between the clusters varies with to the similarity of the clusters.  
     
     
         23 . A computer program product that detects polymorphisms in sample nucleic acid sequences, comprising: 
 computer code that receives a plurality of sets of hybridization affinity information, each set of hybridization affinity information including hybridization affinities between a sample nucleic acid sequence and nucleic acid probes;    computer code that hierarchically clusters the plurality of sets of hybridization affinity information into a plurality of clusters such that all sets of hybridization affinity information in each cluster are more similar to each other than to the sets of hybridization affinity information in another cluster;    computer code that analyzes the plurality of clusters to detect if there are polymorphisms in the sample polymers; and    a computer readable medium that stores the computer codes.    
     
     
         22 . The computer program product of  claim 21 , wherein the computer readable medium is selected from the group consisting of floppy disk, tape, flash memory, system memory, hard drive, and a data signal embodied in a carrier wave.