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How much DNA does forensics need to get a good sample?

I got my new drivers license today. I would have kept my old one, but the guy working there said they were sending it to Jefferson City, the capitol of Missouri. They already have all the info on the card in their database. How much material do forensics need to get a good dna sample?

That would be a really clever way of building a database without people knowing if you could isolate a person's dna from the other people that touched the card.

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cdubnbird6 years ago
we amplify DNA from mouth swabs using PCR and while very small samples can be amplified it's simply the fact of getting the sample into a tube and that you lose more and more of a sample as you transfer it from varying containers
Re-design6 years ago
They just want to prove that it has been destroyed.

There is NO way they could get YOUR dna off the license. There may be 50 different kinds of dna there.

Yours, the clerks, your girlfriend, the three cops that gave you tickets last night, the bouncer at the biker bar, the bouncer at the gay bar...
Vorenus (author)  Re-design6 years ago
That was my second thought; maybe they want to make sure it's destroyed. Then I talked to my mother who had hers renewed a month ago. Why didn't they take hers? If you're concerned with the future, you only need younger generations dna. It's how I would do it; assuming you could get the 50 different kinds of dna off the card and segregated. After you had the 50, it would be mostly about pattern recognition. What percentage of the population is in jail, or has been in jail at one time? And they have all the cops dna; process of elimination. The bouncers and the bartenders dna will be on the most cards. Pair it with financial records and spending patterns and it would be a lot easier; especially if they know the occupations. Thanks for the reply. Fascinating info.
lemonie6 years ago

You can use PCR on nanogrammes of DNA, but steve has spotted an obvious problem with your particular line of thinking.

L
You mention the main reason why its very hard to do - DNA amplification by PCR amplifies EVERY DNA sample on the card, bacteria, people, the cat, and makes extracting a unique signature sample very hard to do.
rickharris6 years ago
Very little as the latest processes can clone DNA from a very small sample - say a swab scraping of the inside of your mouth. A drop of blood would be more than enough.