R.M. Fourney, K.L. Bowen, C.J. Frégeau, B. Leclair, J.H. Elliott and B.D. Gaudette
DNA Methods and Database Biology Services, Forensic Laboratory Directorate, Royal Canadian Mounted Police, Ottawa, Ontario, Canada

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In the beginning there was silver staining STRs which eventually evolved into fluorescent analysis and semi-automated detection of STR alleles. Since December 1991, the Royal Canadian Mounted Police forensic lab services have embraced STR technology and launched a major research and training program to introduce this method of DNA analysis with the intention of eventually replacing RFLP VNTR procedures. Our current PCR casework approach employs the ABD 377 DNA Sequencer, three STR multiplexes composed of 10 STR loci and one gender discrimination locus providing a "most common" discrimination potential of 1 in 186 million (based on a Canadian Caucasian population).

During our first year of implementation and introduction of STRs into casework, numerous lessons were learned. These lessons range from the scientific and technical aspects of the new technology (e.g. background fluorescence, dilution ratios with mixtures, missing bands etc.) to questions challenging existing casework management strategies, efficiency measures, database plans and quality assurance concerns. Through practical examples, this presentation discusses problems that were encountered using automated fluorescent technology and their solutions which set the foundation for a valid and reliable forensic STR DNA analysis approach.