FIG. 1.

Consider reads which map to a location with genome sequence AAAAAAAAA, which in color space is BBBBBBBB. The reads may differ from the color space genome sequence, because of either SNPs or sequencing errors. The goal of identifying likely sets of sequencing errors and SNPs that would produce the given read is complicated by the dependence between adjacent colors. Valid color substitutions are restricted to those which change the read sequence locally, while sequencing errors are not restricted. Above are a set of reads that map to the genome location in color space, along with a set of possible interpretations of the read as results of sequencing errors and SNPs. Determining the combination of SNPs and sequencing errors which affected any single read is difficult, ComBs statistical model allows the likely interpretation to be made using the entire collection of reads.