DNA Extraction
At IDENTIGENE, DNA is isolated from buccal swab (and all other) specimens using an organic extraction process. When buccal swab specimens are received at our laboratory, the cotton tips are snapped off into small specimen tubes containing a solution of an enzyme called Proteinase K. This enzyme breaks down proteins that are complexed to the DNA molecules in the chromosomes found in the nucleus of the cells. This enzymatic breakdown occurs best at a temperature of 56° C, so specimens are incubated at that temperature for several hours (usually overnight).
The next morning, a mixture of the organic chemicals phenol and chloroform is added to the specimens. These chemicals strip proteins and other cellular debris from the DNA and cause the solution to separate into two layers: an organic phase containing the proteins and other cellular debris, and an aqueous layer containing the DNA.
The aqueous layer is collected and transferred to another tube. In this tube the aqueous layer is made highly ionic and alcohol is added to it. This causes the DNA to precipitate out of solution. It is pelleted to the bottom of the tube in a high-speed centrifuge, washed with alcohol, and pelleted a second time. After this the alcohol is evaporated. Finally, the remaining dried DNA is resuspended in a buffer to bring it to the correct concentration for amplification using the Polymerase Chain Reaction (PCR). The DNA isolated from one swab is usually about 5 mg (a microgram is one millionth of a gram).
Sample Collection
Sample Shipment
Sample Login
DNA Extraction
DNA Amplification
Laser Detection
Result Analysis
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