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Forensic Science Forensic Serology • The study of body fluids for forensic purposes • Most useful : Blood • 2 aspects to look at forensically – Biological: serology – Physics: blood pattern analysis Blood Evidence • Blood samples – Can be analyzed to determine blood type and DNA, which can be matched to possible suspects. • Blood droplets – Can be analyzed to give clues to the location of a crime, movement of a victim, and type of weapon. • Blood spatter – Can be analyzed to determine patterns that give investigators clues to how a crime might have happened. William Harvey • English physician • 1628 • Discovered circulation Karl Landsteiner • • • • 1930 Austrian Won the Nobel Prize Discovered 4 blood types How can blood be used • Cannot Identify • CAN exlude Tasks for using blood 1. 2. 3. 4. Determine if its blood Determine if its human or animal Examine it for age, sex and blood type Examine for other characteristics ( drugs, disease, etc) Parts of Blood • Slightly Alkaline ( basic) • Composed of water, cells, enzymes, proteins & inorganic substances • Carry nutrients, oxygen and waste ( including CO2) What makes up our blood? • RED BLOOD CELLS (Erythrocytes) – The most abundant cells in our blood; they are produced in the bone marrow and contain a protein called hemoglobin that carries oxygen to our cells. Also carry CO2. • WHITE BLOOD CELLS (Leukocytes) – They are part of the immune system and destroy infectious agents called pathogens. • PLASMA – This is the yellowish liquid portion of blood that contains electrolytes, nutrients and vitamins, hormones, clotting factors, and proteins such as antibodies to fight infection. • PLATELETS (Thrombocytes) – The clotting factors that are carried in the plasma; they clot together in a process called coagulation to seal a wound and prevent a loss of blood. What makes up our blood? • Serum – Liquid portion of the blood left over after all cells have been removed. Blood Facts The average adult has about FIVE liters of blood inside of their body, which makes up 7-8% of their body weight. Blood is living tissue that carries oxygen and nutrients to all parts of the body, and carries carbon dioxide and other waste products back to the lungs, kidneys and liver for disposal. It also fights against infection and helps heal wounds, so we can stay healthy. There are about one billion red blood cells in two to three drops of blood. For every 600 red blood cells, there are about 40 platelets and one white cell. http://www.bloodbankofalaska.org/about_blood/index.html Genetics of Blood Types • Your blood type is established before you are BORN, by specific GENES inherited from your parents. • You inherit one gene from your MOTHER and one from your FATHER. • These genes determine your blood type by causing proteins called AGGLUTINOGENS to exist on the surface of all of your red blood cells. What are blood types? Blood Types There are 3 alleles or genes for blood type: A, B, & O. Since we have 2 genes, there are 6 possible combinations. AA or AO = Type A BB or BO = Type B OO = Type O AB = Type AB http://learn.genetics.utah.edu/units/basics/blood/types.cfm What causes different blood types? Antigens: Agglutinogens- proteins on the surface of the cells Antibodies: Proteins in serum that attack certain antigens. Cause the thing they attack to clump/clot ( aggultinate) A person with antigen A will NOT have anti-A antibodies How common is your blood type? 46.1% 38.8% 11.1% 3.9% Blood Transfusions A blood transfusion is a procedure in which blood is given to a patient through an intravenous (IV) line in one of the blood vessels. Blood transfusions are done to replace blood lost during surgery or a serious injury. A transfusion also may be done if a person’s body can't make blood properly because of an illness. Who can give you blood? Universal Donor People with TYPE O blood are called Universal Donors, because they can give blood to any blood type. People with TYPE AB blood are called Universal Recipients, because they can receive any blood type. Rh + Can receive + or Rh - Can only receive Universal Recipient Rh Factors • Scientists sometimes study Rhesus monkeys to learn more about the human anatomy because there are certain similarities between the two species. While studying Rhesus monkeys, a certain blood protein was discovered. This protein is also present in the blood of some people. Other people, however, do not have the protein. • The presence of the protein, or lack of it, is referred to as the Rh (for Rhesus) factor. • If your blood does contain the protein, your blood is said to be Rh positive (Rh+). If your blood does not contain the protein, your blood is said to be Rh negative (Rh-). http://www.fi.edu/biosci/blood/rh.html A+ AB+ BAB+ ABO+ O- Forensic Science Blood Typing Lab Activity The Crime Report A small pool of blood and a weapon was found near a garbage dumpster. After examining the area, the CSI on the scene discovered a body in the garbage dumpster and identified him as Earnest “One-Eyed” Earl. Earl had a wound to his chest that will be analyzed by the medical examiner. The CSI tested blood samples from the blood pool and the weapon at the crime scene. It was determined that it was human blood, but he needs to know the blood type to help identify if it was from the victim or the person who murdered him. He has come up with three suspects that either knew the victim or were seen in the area before the body was discovered. He would like to question them further while he waits for DNA test results. Follow your teacher’s directions to complete the lab. Remember to be careful to prevent cross-contamination of the blood samples! Image: http://www.fbi.gov/publications/leb/2005/apr2005/apr2005leb_img_3.jpg Blood Typing Test We will be determining blood types using Anti-A serum, Anti-B serum, and Anti-RH serum. Use the chart to help you determine the blood type of each sample and its Rh factor (+ or -). Type Reaction w/ Anti-A Serum Reaction w/ Anti-B Serum A + - B - + AB + + Clumping = + (Positive) No Clumping = - (Negative) O Rh Serum - Clumping = Rh+ blood DIRECTIONS: Step 1: Label the three cups in your kit as Anti-A, Anti-B, and Anti-Rh. Step 2: Place 20 drops of the blood sample in each cup. Step 3: Place 10 drops of the anti-A serum in the A cup. Step 4: Place 10 drops of the anti-B serum in the B cup. Step 5: Place 10 drops of the anti-Rh serum in the Rh cup. Step 6: Use a clean toothpick for each sample and stir for 30 seconds. Step 7: Record your observations in the correct section on the back of the page and use the reaction chart at the top of this page to determine the blood type. Step 8: Complete the other sections using information from your classmates. Clumping = Positive Result Agglutination = Clumping = Positive Reaction Type Reaction w/ Anti-A Serum Reaction w/ Anti-B Serum A + - B - + AB + + O Rh Serum - Clumping = Rh+ blood A Rh B What is this person’s blood type? Answer: A+ Use + or – to show the test results for each sample and then determine the blood type. Results + = Clumping - = No clumping Conclusion What do your results show? What would you do next in the investigation? Microscopic Views Look at 4 different samples of Blood Data: Draw the sample on Low power and High Power. Make sure to label the magnification, technique and sample Conclusion: What similarities and differences are there between different bloods? Microscopic Views Fish Blood Bird Blood Horse Blood Frog Blood Cat Blood Dog Blood Human Blood Snake Blood