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Do Now: Take out Notes read Green River Killer articles and discuss in groups Agenda:

Do Now: Take out Notes read Green River Killer articles and discuss in groups Agenda: Green River Killer Intro to Serology HW: investigate further as to way Ridgway was able to pass a lie detector test in 1984

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Do Now: Take out Notes read Green River Killer articles and discuss in groups Agenda:

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  1. Do Now: • Take out Notes • read Green River Killer articles and discuss in groups • Agenda: • Green River Killer • Intro to Serology • HW: • investigate further as to way Ridgway was able to pass a lie detector test in 1984 • determine why the hair and saliva samples proved to insufficient evidence to prosecute in 1987

  2. Answer the following questions • Why was Gary Ridgway initially considered a suspect? • What evidence was collected at Ridgway’s residence with the aid of a search warrant? • What forensic advancement led to the conviction of Gary Ridgway? • What additional trace evidence helped connect Ridgway to the murders? • Was Ridgway found guilty? • How many total victims?

  3. Karl Landsteiner • 1901 discovered the ABO typing of blood • found that not all blood is the same How did this change for Dr.’s trying to transfuse blood? What is the A-B-O system? Why do Forensics scientists no longer use the system?

  4. Nature of Blood • The word blood refers to a highly complex mixture of cells, enzymes, proteins, and inorganic substances. It makes up 1/12th of the human body. • Plasma,(55% of the blood), which is the fluid portion, is composed principally of water. • Red blood cells (erythrocytes), white blood cells (leukocytes), and platelets are the solid materials suspended in plasma. • Antigens, usually proteins, are located on the surface of red blood cells and are responsible for blood-type characteristics.

  5. Serology • The term serology is used to describe a broad scope of laboratory tests that use specific antigen and serum antibody reactions. • Serum is the liquid that separates from the blood when a clot is formed • The identity of each of the four A-B-O blood groups can be established by testing the blood with anti-A and anti-B sera.

  6. Blood Typing • More than 15 blood antigen systems have been identified, but the A-B-O and Rh systems are the most important. • An individual that is type A has A antigens on his/her red blood cells, type B has B antigens, AB has both A and B antigens, and type O has neither A nor B antigens. • Rh factor is determined by the presence of another antigen, the D antigen. • People having the D antigen are Rh positive; those not having the antigen are Rh negative.

  7. For every antigen there is a specific antibody that will react with it to form clumps known as agglutination. • Thus, if serum containing anti-B is added to red blood cells carrying B antigen, they will immediately react. • What is an antigen and how is it useful in individualizing blood? • What is an anti-body and what happens when an antibody reacts with its specific antigen?

  8. Identification of Blood with Antiserum

  9. Blood type distribution in US • Who is the universal donor? universal recipient?

  10. Blood Type Test • Blood Test • Saliva Test • Secretors • 80% of the world’s population • secrete their blood type antigens in their saliva

  11. Heredity and Paternity • The transmission of hereditary material is accomplished by means of microscopic units called genes, located on chromosomes. • Alternative forms of genes that influence a given characteristic (such as eye color or blood type) are known as alleles. • Paternity testing has historically involved the A-B-O blood typing system, along with blood factors other than A-B-O. • Currently, paternity testing has implemented DNA test procedures that can raise the odds of establishing paternity beyond 99 percent.

  12. Inheritance of Blood Types The Punnet square below demonstrates the possible blood types of the offspring of a type AB mother and a type O father. IA IB i i Blood types: 50% A 50% B

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