Medical DNA test question

lisab

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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?
 
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.
 

lisab

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Science Advisor
Gold Member
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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 :rofl: .
 
Yes they are. To be precise they are specific to certain conserved loci in the human genome.
 

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