HumanHap300-Duo and HumanHap300-Duo+ Genotyping BeadChips enable researchers to analyze two samples simultaneously, with more than 634,000 total tag SNPs on a single BeadChip, 317,000 tag SNPs per sample. These products deliver a level of genomic coverage that would require more than twice the number of randomly selected SNPs. The multi-sample format makes these products useful for loss of heterozygosity (LOH) and comparative genomic hybridization (CGH) studies.