Science & Criminal investigation 1st lesson: Blood grouping The ability to type blood is an invaluable tool in the fields of medicine and criminology. Storyline At 1:00 a.m., someone breaks a window in the back of a store and robs the safe. On the way out, the thief cuts himself (or herself) on a piece of broken glass. You are a forensic detective called to the scene. You test a sample of blood left behind by the thief. While you are there, police bring in 3 suspects with a cut forearm who were arrested just three blocks from the store. You take a sample of each suspect’s blood and mix it with sera. You belong to CSI (Crime Scene Investigation) and you have to give your conclusion to help police resolve the investigation. Problem: ______________________________________________________________________________________ ? Objectives • To raise the problem after reading the storyline • To understand and perform blood grouping test • To fill in the table sharing information between groups • To give the policeman the conclusion in a few words Material 1 blood typing slide 4 blood samples : one coming from the smear on the window (sample 4) and the others coming from 3 suspects (samples 1, 2, 3) anti-Rh (D) serum anti-A serum anti-B serum mixing sticks (blue, yellow, and white) Organisation → Class is splitted into 2 groups of 12 students standing for a team of scientits working for a crime lab. → In a group you have to form 4 small groups of 3 to share tasks : → In a small group : one is giving instructions while second is performing the test and third is establishing a model for agglutination. When you're ready, one of you in each group will meet the policeman to give him the lab conclusion. Instructions for blood grouping test (not necessary if you pay attention to your teacher's explanations at oral!) 1. Using the dropper vial, place a drop of the first blood sample in each well of the blood typing slide. Replace the cap on the dropper vial. Always replace the cap on one vial before opening the next vial to prevent cross contamination. 2. Add a drop of anti-A (blue) to the well labeled A. Replace the cap. 3. Add a drop of anti-B serum (yellow) to the well labeled B. Replace the cap. 4. Add a drop of anti-D serum (clear) to the well labeled Rh. Replace the cap. 5. Using a different color mixing stick for each well (blue for anti-A, yellow for anti-B, white for anti-D). Remember to discard each mixing stick after a single use to avoid contamination of your samples. 6. Carefully examine the thin films of liquid mixture left behind. If a film remains uniform inappearance, there is no clumping (=agglutination). If the sample appears granular, clumping has occurred. Determine the blood type of the sample using the data table below. Answer yes or no as to whether clumping occurred in each sample. A positive clumping reaction indicates the blood type. 7. Record the results for the first blood sample in the data table. Data table Red blood cell from the window Serum anti-A Serum anti-B Serum anti-D Conclusion + = clumping

Red blood cell from suspect 1

Red blood cell from suspect 2

Red blood cell from suspect 3

Document

Models to cut with scissors

Science & Criminal investigation 2nd lesson: Hair evidence Hair and fibre are two of the most important resources in Forensic Science and are often responsible for providing valuable clues as to identity of an assailant or attacker. Background Several strands of hair have been found clutched in the hand of a murdered man. The investigating detectives discovered three different people visited the man at different times on the date of his murder. These three people are the only suspects in the murder and have been asked by the detectives to donate a sample of their hair. - Suspect A, a disgruntled employee fired by the murdered man the day before the crime, claims that he had come to see the man to beg for his job back. - Suspect B, the ex-wife of the murdered man, says she came to see the man to discuss alimony and child support checks that he had not paid. - Suspect C, an out-of-work model whom the man had been dating, claims she visited the man to discuss getting a loan from him to pay for her weekly hair stylist sessions. -Suspect D, a suspected member of the local organized crime family, and a stockholder of the murdered man’s company, claims he visited the man to discuss a plan to increase profits for the company. All suspects have claimed that the man was alive when they left his house. Your lab has collected the hair samples from the suspects to analyze. You are asked to discover as much information as possible about all of the important characteristics of each suspect hair sample. Problem:_______________________________________________________________________________________ ? Objectives • To use microscope for hair structures identification. • To take information in documents to help you fill in the data table. • To share results in the team lab in order to give the policeman the conclusion. Material

→ Blank slides and coverslips + Dissecting kit + 1 microscope → Hair samples (Evidence found in the hand and 4 suspects) Organisation → Class is splitted into 2 groups of 12 students standing for a team of scientits working for a crime lab. → In a group you have to form 4 small groups of 3 to share tasks : → In a small group : one is giving instructions while second is performing the test and third is filling in the data table. When you're ready, one of you in each group will meet the policeman to give him the lab conclusion. Data table Evidence

Suspect A

Suspect B

Straight or curly Color Cuticle patterns Medulla patterns Diameter Word box Evidence = clue = indice Forensic = légal Disgruntled = mécontent Alimony = pension alimentaire To date = fréquenter, sortir avec Loan = emprunt Stockholder = actionnaire

Suspect C

Suspect D

Document 1: Hair structure

Document 2: Cuticle patterns

Document 3: medulla patterns

Write your report below :

Science & Criminal investigation 3rd lesson: DNA evidence Hair thickness, medulla and scales patterns aren't definitly sufficient to identify someone. As for blood type, many people have the same group ! So the best evidence in crime scene remains DNA. But investigators have to find cells left by the criminal and to recover DNA for analysis... Pb: __________________________________________________________________________________________ ? Objectives Documents - To understand the principle thanks to the video and the documents. - To perform electrophoresis following oral instructions - To explain in a few words each stage of the test - To draw the result you got at end of the electrophoresis

Document 1 : PCR Document 2 : STR Document 3 : Electrophoresis + online VIDEO : https://vimeo.com/69239594

- To give your conclusion Matérial DNA from the scene crime 4 samples of DNA coming from suspects in eppendorf tubes Buffer solution at pH 8,3 Developing solution (Azure) Electrophoresis apparatus + Power supply 125V Agarose gel with 6 wells (20µL) micropipette (0-20 μl) micropipette tips (yellow) Gloves NB: DNA electrophoresis takes about 1h ! We must start it as soon as possible in order to analyse results. Document 1: PCR The polymerase chain reaction (PCR) is a technology in molecular biology used to amplify a single copy or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence. Thanks to PCR, 1 nanogramme of DNA can be copied and used by several labs.

Did you know? In order to copy DNA and amplify it using the polymerase chain reaction (PCR), an enzyme (DNA polymerase) is needed which is active at high temperature. The DNA polymerase of the Bacteria Thermus aquaticus (discovered in a hot spring of Yellowstone park in 1966), called Taq polymerase, fills the bill. During the successive heating cycles of PCR, Taq polymerase is not destroyed, but continues to work. Very used in DNA fingerprinting, it has become the basis of a $300,000,000 industry.

Document 2: Short Tandem Repeat

Exemple with two individuals :

A short tandem repeat consists of a unit of two to thirteen nucleotides repeated hundreds of times in a row on the DNA strand. STR analysis measures the exact number of repeating units. The variable (polymorphic) nature of the STR regions that are analyzed for forensic testing intensifies the discrimination between one DNA profile and another. Did you know? Colin Pitchfork is a convicted British murderer and rapist. Arrested on 19 September 1987,he is the first person convicted of a crime based on DNA fingerprinting evidence.

Document 3: Electrophoresis Gel electrophoresis can separate nucleic acids that differ in size. How far a DNA molecule travels is inversely proportional to its length. After the current is turned off, a dye is added; this reveals the separated bands by fluorescing in ultraviolet light. NB : DNA has a negative charge at basic pH 8.2 so that it moves from the cathode to the anode. When the electric current is applied, the longer molecules move more slowly through the gel while the smaller molecules move faster.

Exemple of results

Draw your result below with correct caption