Mohammed A. Tahir, Ph.D., Sandra M. Sovinski, B.S. and Gabriel E. Novick, M.D. Ph.D.
Indianapolis-Marion County Forensic Services Agency, 40 South Alabama Street, Indianapolis, Indiana 46204

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Utilization of Polymerase Chain Reaction (PCR) for forensic purposes has revolutionized forensic DNA typing methods. Before the discovery of PCR, it was impossible to type forensic samples which were minute in quantity, old, or degraded. Sometimes it is very difficult to find high quality reference DNA to compare with evidence samples. In the case of missing persons, it is often impossible.

We have successfully extracted and typed DNA from urine, perspiration, razor blades, chewing gum, a wrist watch, ear wax, a toothbrush, envelope flaps and postage stamps for DQA, LDLR, GYPA, HBGG, D7S8 and GC loci. The DNA was extracted using a slightly modified FBI organic extraction protocol followed by Centricon 100 clean-up. Approximately 8 ml of TE was passed through each sample to make sure the DNA was very clean. The final volume of 40-60 µl was recovered and passed through Microcon 100 to concentrate the sample to a volume of 10 µl. The material was subsequently used for quantitation and amplification.

We recognize the potential application of the above mentioned resources in cases were there is no reference DNA to compare with evidence samples. In such situations, a DNA extract from a piece of bone can be linked to the DNA extracted from an individual’s razor, toothbrush or other potential sources of cellular material. Such sources of secondary standards should prove most useful when there are no family members to provide alternative standards for establishing identification through paternity testing.