Methods for analyzing omics data and using the omics data to determine genetic distances and/or difference scores among a plurality of biological samples to so further determine the homogeneity of a group having a plurality of biological samples and/or exclude an individual biological sample from a group of biological samples as an outlier are presented. In preferred methods, a plurality of local differential string sets among the plurality of sequence strings is generated using a plurality of local alignments. The local different string is an indicative of genetic difference between one sequence string and one of the rests of the sequence strings among the plurality of sequence strings. From the plurality of local differential string sets, a plurality of difference scores among the plurality of sequence strings can be determined.