• Question: how do the police find out who you are by using your DNA?

    Asked by paul12345 to Judith on 11 Jun 2012.
    • Photo: Judith Sleeman

      Judith Sleeman answered on 11 Jun 2012:

      All of us have, in our DNA, lots of little repetitive sequences (called microsatellites) as well as genes. These are different in different people. If the police can find a small amount of DNA at a crime scene (from blood, roots of hair, skin etc), then the forensic scientists can use a technique called polymerase chain reaction (PCR) to make lots of copies of these repetitive sequences and look at them. Because we all have different versions of these sequences, if yours match the ‘profile’ from the crime scene, you’re nicked!

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