Quantitation of Male and Female DNA in Mixed Biological Samples Using Quantitative Amplification of the Human Amelogenin Locus

Abstract

Q-TAT provides useful information in the quantitative analysis of male and female mixed biological samples. With high amount of male DNA and a minor female contributor, no significant difference was observed between observed and expected X/Y ratios. For samples containing high amounts of female DNA in the presence of a minor male contributor, the expected ratio was slightly lower than the observed ratio for ratios greater than 1 female:5 male. Major/minor peak ratios produced by STR typing were similar to those produced with Q-TAT for both known mixtures and non-probative evidentiary samples. The Q-TAT quantitation method is able to accurately estimate the relative male and female contributors in mixed samples. For samples in which Q-TAT's accuracy is lacking, it still has the ability to identify the presence of minor male contributor and provide a DNA analyst with enough information to choose the test that will provide the most complete profile.