Skip to content
    Font Size
    A
    A
    A

    DNA Fingerprinting in a Criminal Investigation

    h9991620_001.jpg

    The first step in DNA fingerprinting is to break open the sample cells and collect the DNA. Next, many copies of the DNA are made using polymerase chain reaction (PCR).

    To get the DNA fingerprint:

    • All of the DNA is broken into pieces at certain locations. This is done by chemicals (enzymes) that break each DNA strand at the same place.
    • The DNA pieces are placed at the top of a special gel held in a frame.
    • An electric current is applied to the gel. The current separates the DNA into bands of identical pieces. This process is called electrophoresis.
    • The band pattern is transferred to a nylon membrane containing a radioactive chemical. The chemical makes the bands show up clearly.

    For a criminal investigation, photos of the criminal and suspect DNA are compared. The results in this case show that the suspect is not the criminal.

    ByHealthwise Staff
    Primary Medical ReviewerKathleen Romito, MD - Family Medicine
    Specialist Medical ReviewerSiobhan M. Dolan, MD, MPH - Reproductive Genetics

    Current as ofMarch 12, 2014

    WebMD Medical Reference from Healthwise

    Last Updated: March 12, 2014
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

    Hot Topics

    WebMD Video: Now Playing

    Click here to wach video: Dirty Truth About Hand Washing

    Which sex is the worst about washing up? Why is it so important? We’ve got the dirty truth on how and when to wash your hands.

    Click here to watch video: Dirty Truth About Hand Washing

    Popular Slideshows & Tools on WebMD

    disciplining a boy
    Types, symptoms, causes.
    fruit drinks
    Eat these to think better.
    Balding man in mirror
    Treatments & solutions.
    No gym workout
    Moves to help control blood sugar.
    Remember your finger
    Are you getting more forgetful?
    acupuncture needle on shoulder
    10 tips to look and feel good.
    Close up of eye
    12 reasons you're distracted.
    birth control pills
    Which kind is right for you?
    embarrassed woman
    Do you feel guilty after eating?
    woman biting a big ice cube
    Habits that wreck your teeth.
    pacemaker next to xray
    Treatment options.
    Pink badge on woman chest to support breat cancer
    Myths and facts.

    Pollen counts, treatment tips, and more.

    It's nothing to sneeze at.

    Loading ...

    Sending your email...

    This feature is temporarily unavailable. Please try again later.

    Thanks!

    Now check your email account on your mobile phone to download your new app.

    Women's Health Newsletter

    Find out what women really need.