Medical How Does DNA Separation Work in Cheek Swab Tests?

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DNA tests from cheek swabs are effective despite the presence of bacteria in the mouth. The key to accurate results lies in the use of PCR (Polymerase Chain Reaction) with specific primers that target human DNA, effectively minimizing contamination from bacteria. These primers are designed to be human-specific, focusing on conserved loci in the human genome. Additionally, concerns about contamination from food are acknowledged, but the specificity of the primers helps ensure that only human DNA is amplified during testing.
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DNA tests can now be done from a cheek swab. But since our mouths are full of bacteria, how is that DNA separated from human DNA?
 
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Simply put, generally it is not. But for the tests you perform a PCR using specific primers so that bacterial contamination is not an issue.
 
Are those primers human-specific?

I'm guessing it's not only bacteria that could contaminate a cheek swab, but food could, as well. It would be quite surprising to take a DNA test and find that you're the offspring of celery and a cow :smile: .
 
Yes they are. To be precise they are specific to certain conserved loci in the human genome.
 

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