Table 2. Genotype probabilities and LR calculations are shown at the Penta E locus for a minor contributor.
Allele Pair | TrueAllele | CPI | mCPI | ||||||||
prior | likelihood | posterior | LR | likelihood | posterior | LR | likelihood | posterior | LR | ||
7 | 7 | 4.3% | 1 | 17% | 1 | 67% | |||||
7 | 10 | 3.3% | 2 | 1 | 13% | ||||||
7 | 12 | 7.1% | 2 | 1% | 1 | 28% | |||||
7 | 14 | 1.9% | 1 | 8% | 1 | 30% | |||||
10 | 10 | 0.6% | 1 | 1 | 2% | ||||||
10 | 12 | 2.7% | 986 | 98% | 37 | 1 | 11% | 4 | 0 | ||
10 | 14 | 0.7% | 1 | 3% | |||||||
12 | 12 | 2.9% | 8 | 1% | 1 | 11% | |||||
12 | 14 | 1.6% | 1 | 1 | 6% | ||||||
14 | 14 | 0.2% | 1 | 1% | 1 | 3% | |||||
Total | 100% | 100% | 100% |
Three different mixture interpretation methods were used, TrueAllele, CPI and mCPI. Over the sample space of possible allele pairs, each method has a likelihood function and posterior probability distribution. The LR gives the ratio of posterior to prior probability at comparison allele pair 10,12 (italicized row). TrueAllele’s greater LR indicates more use of the STR data than CPI. mCPI discarded too much data, and could not yield a match statistic.