Modelling allelic drop-outs in STR sequencing data generated by MPS

The Poisson-gamma model was used to estimate the rate of drop-outs of (1) single contributor dilution series experiments and (2) the minor contributor in two-person mixture samples. We examined the predictive capabilities of the model by comparing the observed and expected Brier scores of each sample. We derived the expected Brier scores and their variances to create asymptotic confidence intervals of the Brier scores. We found that the Poisson-gamma model performed well when using the work-flow data base, but that the replicate approach is not necessarily a viable option.