| Abstract: | The performance of typing group-specific component (Gc) in bloodstains by two isoelectric focusing methods followed by its detection with silver staining has been compared with an established forensic system of typing phosphoglucomutase (PGM1) locus phenotypes by isoelectric focusing (IEF) in 1 mm gels. For Gc typing ultra-thin isoelectric focusing (UTIEF) gels and immobilized pH gradient (IPG) gels were used. Both laboratory prepared stains and casework stains were examined. The Gc UTIEF method is approximately eight times more sensitive than the existing PGM1 1 mm IEF method for control and casework stains. However, on average, a larger amount of stain was taken from casework stains than control stains for each typing system. A total of 53 casework stains were examined. Comparable success rates of 62% and 64% were obtained for typing Gc on UTIEF gels and PGM1 by 1 mm IEF, respectively. A success rate of 55% was obtained for typing Gc on IPGs. Bloodstains that were over 200 days old were successfully grouped by all three methods. |
