Recovery of genomic DNA from archived PCR product mixes for subsequent multiplex amplification and typing of additional loci: forensic significance for older unsolved criminal cases

Abstract

A method for genomic DNA recovery from different types of PCR product mixes suitable for multiplex amplification and typing using the Profiler Plus頓TR typing system has been investigated. The application of this method is of significance in cases where the original DNA samples have been exhausted due to repeated typing analyses in an effort to maximize their evidentiary value. Such cases typically involve samples analyzed using the available DNA typing systems of the time which gave a markedly lower power of discrimination, either alone or in combination, compared to that of modern multiplex STR typing systems. It was found that an effective method for recovering genomic DNA from HLA-DQA1 + PM and CTT triplex amplification mixes, suitable for reproducible achievement of the complete Profiler Plus頰rofile, involved the use of Amicon Microcon-100 microconcentrators. Interestingly, this method was not required to achieve the complete nine STR profile using D1S80 amplification mixes.