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Skip Navigation LinksCrime Laboratory Service : Forensic Genetics

The Forensic Genetics Laboratory analyzes biological fluids and tissues such as blood, semen, muscle and bone. The DNA contained in these materials is purified and tested to obtain a DNA profile that may link evidence found at a crime scene to an individual.

Likewise, non-matching DNA profiles can point investigators away from a particular individual. A DNA profile recovered from two or more crime scenes can indicate the same individual was present at more than one crime scene. In addition, DNA testing can establish parentage and can positively identify human remains.


The Polymerase Chain Reaction, or PCR, is used to prepare large quantities of specific DNA regions from small samples recovered from crime scenes.  The laboratory utilizes automated genetic analyzers that subject the DNA to capillary electrophoresis to determine DNA profiles.

The laboratory participates in the FBI Combined DNA Index System, or CODIS, a network of local, state and national DNA databases.  CODIS links DNA profiles of evidence from unsolved crimes to DNA profiles from convicted offenders and from DNA profiles of other crimes.

The Harris County Institute of Forensic Sciences has developed a DNA Collection Guide to assist officers in obtaining the best possible DNA samples from crime scenes.  The guide provides step-by-step instructions for collecting, labeling and packaging of DNA samples and includes a list of the supplies needed to ensure success.


DNA Card

Click here to download and print the DNA Collection Guide.

DNA Presentation (PPT 41MB)



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