discordance compared to Illumina OMNI2.5M genotypes produced by the 1000 Genomes Project. For this comparison, we focused only on genotypes from 365 samples shared across the 3 sample sets and at 42,244 SNP sites. We calculated percentage discordance for the 3 possible genotypes consisting of reference (REF) and alternate (ALT) alleles as well as an overall non-reference allele discordance rate (NRD). Results are shown in Supplementary Table 2.