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DNA – analysis part 1

DNA - analysis part 1

Having looked now at what DNA is, we need to look at how we undertake its analysis.

The steps that take us from the body fluids stain to the DNA profile are described. The video closes with a revisit to one of the basic principles of crime scene examination, namely “Preserve”, and shows why protective clothing and avoidance of contamination (for example by coughing or sneezing) are so important.

The key technique used is Polymerase Chain Reaction (PCR). The video in the “See also” section below on the Polymerase Chain Reaction (PCR) describes the process that makes forensic short tandem repeat (STR) analysis possible. Again the material is more technical than we have been used to seeing, so watching the video on the polymerase chain reaction more than once (and maybe taking some notes) will help you understand what’s going on.

The last of the important steps in the process is the separation of the individual components of the short tandem repeat product mixture produced by the PCR reaction; Capillary electrophoresis is the method used to do this.

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Introduction to Forensic Science

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