Distribution statistics on the number of UMs found in an SNP sequence: (A) the SNPs assigned by both UM and NCBI (National Center for Biotechnology Information); (B) the NCBI assignable/unassignable SNPs. “NCBI assignables” refers to the SNPs that were assigned to chromosomes 1–24 in dbSNP, and “NCBI unassignables” refer to those that were not assigned. The comparison between the UM and NCBI assignments was made using the NCBI assignables. Note that, according to the scheme of the UM method, SNPs with a single UM will be uniquely assigned and those with two, three, or four UMs will always be assigned as ‘multiple’ if they have more than one UM cluster (see Methods), explaining the dip in the percentage agreement plot.
