BRCA1 and neoplasm: The preferential loss of the opposite allele can be visualized in Figure 3c, where all the heterozygous tumor DNA, together with their matching normal DNA, were subjected to a BRCA1 4096+3A>G SNP assay, and dots in the allelic discrimination plot were subsequently colored differently, according to whether they originated in a tumor or a normal sample (instead of conventional automatic coloring by genotype).