Resolving Individuals Contributing Trace Amounts of DNA to Highly Complex Mixtures Using High-Density SNP Genotyping Microarrays
To give insight into the intuition behind our method, we present for a given SNP three different scenarios for the possible allele frequency of the person of interest corresponding to the genotypes AA, AB, and BB.
The allele frequencies of the reference population, person of interest, and the mixture are described as Mi, Yi, and Popi respectively. We see that the distance measure is greater (and positive) when the Yi of the person of interest is closer to the Mi of the mixture than to the Popi of the reference population. Similarly, the distance measure is smaller (and negative) when the Yi of the person of interest is closer to the Popi of the reference population than to Mi of the mixture. Our test statistic is then the z-score using this distance measure.