A. Al-Khayat1, F. Al-Shamali1 and N. Watson2
1Dubai Police, Crime Laboratory, CID, Dubai, United Arab Emirates
2Strathelyde University, Forensic Science Unit, Glasgow, UK
For its high degree of heterozygosity, the D1S80 locus has gained a wide popularity in the forensic community. Precise sizing of the amplified product is essential for correct DNA typing. Capillary electrophoresis (CE) can be used to separate DNA molecules such as PCR fragments. The principal advantages of CE over slab gel electrophoresis lies in the shorter separation time, reduced amount of sample required, increased efficiency and resolution of separation.
Capillary electrophoresis of the D1S80 was performed using the Beckman P/ACE™ system 5510 equipped with a laser-Induced Fluorescence (LIF) detector in the reverse polarity mode. Analysis of PCR products was conducted using the eCAP ds DNA 1000 kit. We have used CE to separate and analyze amplified polymorphic alleles from the D1S80 locus both with allele ladder and a population study samples. PCR products or allelic ladder were subjected to dialysis to remove excess salts using centricon-100 micro concentrator and loaded diluted with milli-Q grade water. Several optimization tests were performed, using D1S80 allele ladder and phi x 174 while varying capillary length, temperature and voltage. Allele size were determined by plotting retention time versus molecular weight. The separation exhibited satisfactory run-to-run reproducibility while some variation occurred in day-to-day reproducibility and that might be due to plugging or current fluctuation experienced. The use of internal standard and a better optimized method is required for routine application. The results of these experiments will be discussed in detail. Our experience indicate separation efficiency of D1S80 alleles using CE allowing automated forensic DNA analysis.
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