DNA Fingerprinting

Sources of human DNA at a crime scene? Body fluids: blood, semen, saliva, urine, faeces, vomit Tissues: skin, bone, hair, organs, fingernail scrapings Fingerprints Weapons Bites Discarded chewing gum Cigarette butts Handkerchiefs and discarded tissues Used envelopes and stamps Cutlery Used cups, mugs and bottled or canned drinks Clothing Hairbrushes Toothbrushes Shoes and other footwear Plasters Used syringes

What do you know so far? Your task:- In pairs with A3 paper draw a mind map of your current knowledge to do with genetics, DNA and DNA analysis. You have 2 minutes! Swap your mind map with the pair next to you. Can you add any more information to theirs? You have 2 more minutes!

How can DNA be used to identify an individual? DNA 0.1% of our DNA is unique Every single cell in our bodies contains DNA, the genetic material that programs how cells work percent of human DNA is the same in everyone, meaning that only 0.1% of our DNA is unique! Each human cell contains three billion DNA base pairs. Our unique DNA = 0.1% of 3 billion = 3 million base pairs The only exception is identical twins, who share 100% identical DNA.

Using DNA in a court case c02.sci.life.gen.sheppard/

How does DNA Fingerprinting work? Which suspect is guilty? Is there enough DNA to analyse? Is there enough DNA to analyse? How does this work?

Tandem repeats & restriction enzymes Everyone except identical twins have varied numbers of tandem repeats in their non-coding ‘junk’ DNA.

Solving a crime... Go to: dc02.sci.life.gen.creatednafingerprint/ dc02.sci.life.gen.creatednafingerprint/ Click on ‘view’ and work through the presentation, answering the questions on the worksheet as you go. Now answer questions based on 3 real-life cases that used DNA fingerprinting

Well done…Now all you have to do is convince a jury! Your Task:- Write a word report describing how DNA fingerprinting can be used to prosecute a criminal with evidence from the crime scene. jury of your peers This should be aimed at a jury of your peers (who do not have a degree in forensic science!)