At 07:13 PM 1/28/2003 +0100, Thomas Shaddack wrote: >But now how to avoid leaving random DNA traces? What about giving up on >NOT leaving traces and rather just use eg. a spray with hydrolyzed DNA >from multiple people, preferably with different racial origin, thus still >leaving fragments like hair or skin cells, but contaminated with wild mix >of DNA, so the PCR-copied mixture will be unusable for reliable >identification?
There indeed might be a DNA mix-master business, like for urine samples, that could be sold on-line. A few of the things that can interfere with PCR testing: - hair pigments - dyes from denim - proteins in the evidence sample can retard the migration of DNA fragments in gels (a problem known as band shift) - Powdered gloves may leave a residue on evidentiary material, which may interfere with DNA analysis. - Small Particle Reagent (SPR), a suspension of molybdenedisulfide powder in a detergent solution, used for fingerprint detection on wet, oily, or dirty surfaces, is a destructive method, and will interfere with just about every other forensic examination that may be required. - Exposure of DNA to external agents such as heat, moisture, and ultraviolet radiation, or chemical or bacterial agents. Such exposure can interfere with the enzymes used in the testing process, or otherwise make DNA difficult to analyze. steve
