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Techniques

Cryogenic Grinding

It is difficult to extract DNA from teeth and bones. Exposing the embedded cells to the surface through cryogenic grinding has proven to be invaluable in recovering sufficient DNA for PCR-based typing.

The BOLD Laboratory provides the following services to investigative agencies: cryogenic grinding, sample preparation and extraction, DNA typing analysis and comparison to known reference samples.

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SPEX 6750 Freezer Mill   Preparing Multiple Samples   Sample in Polycarbonate Tube               Magnetic Chamber   Filling Reservoir with Liquid Nitrogen   Fine Powder Following Two Grinding Cycles for Two Minutes Each

Double Swab Stain Collection

The double swab technique was developed by Dr. Sweet to maximize the yield of salivary DNA evidence from bitemarks found on human skin. The technique was first released for widespread use in 1997. Since then, this method has been found to be useful in the recovery of stains of all dried body fluids found on both skin and other surfaces.

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Wet Swab (wash)   Dry Swab (sponge)

 

Double Swab Technique for Saliva Recovery - Professor David Sweet O.C.