Benoît Leclair¹, George R. Carmody², and Ron M. Fourney^1
1DNA Methods and Database, Central Forensic Laboratory, Royal Canadian Mounted Police, Ottawa, Ontario, Canada
²Dept of Biology, Carleton University, Ottawa, Ontario, Canada

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Implementation of a STR-based DNA typing program for casework at the Royal Canadian Mounted Police Forensic Laboratories was launched in late 1995. It is based on the use of three fluorescent STR multiplexes comprising 10 loci and one gender discrimination locus, providing a "most common" discrimination potential of 1 in 186 million (Canadian Caucasian population database). Analysis of the PCR products is carried out on ABD 377 DNA Sequencers. The experimental design and validation of such a program encompassed a large variety of variables to ensure the robustness of these DNA typing tools in the hands of casework analysts. As with any new technology, strengths and weaknesses of the program are noted during implementation. Some 1600 gels have been run on a network of eleven ABD 377 units located in three RCMP Forensic facilities across Canada. This cumulated experience will be of great benefit for the future design of an anticipated database composed of profiles from violent offenders. This presentation will focus on major trouble-shooting issues encountered including amplicon denaturation, mobility shifts, color bleeding, plate surface problems and data management. In addition, analytical precision studies carried through the gradual implementation of our program have proven to be very informative trouble-shooting tools, providing a deeper understanding of the complex relationship between sizing algorithms, internal lane standard base sequence composition and the impact of chromophor selection on amplicon mobility.