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2009©Forensic Science Today Serology Body fluids and the stains they leave at crime scenes
2009©Forensic Science Today Common Types of Serology Commonly found rape cases are: Blood Hair Sperm
2009©Forensic Science Today History of Blood Typing Karl Landsteiner, recognized differences in human blood Received Nobel Prize in 1929 Critical in blood transfusions A-B-O classification system Rh factor in blood was demonstrated in 1937 More than 100 different blood factors are known today.
2009©Forensic Science Today True or False NNo two individuals, except for identical twins, could be expected to have the same combination of blood factors.
2009©Forensic Science Today Prior to 1990, A-B-O system provided the best means for forensic scientists to link blood to an individual. What changed in 1990?
2009©Forensic Science Today Components of Blood CCellular-Solid materials suspended in plasma that makes up 45% of “blood” Red Blood Cells (RBC)-erythrocytes White Blood Cells (WBC)-leukocytes Platelets PPlasma – 55%- fluid portion of unclotted blood-mostly water Antibodies Enzymes Proteins Serum= liquid that separates from the blood when a clot is formed
2009©Forensic Science Today Blood Stains on Victim’s Jeans Sections removed & initialed for testing
2009©Forensic Science Today Forensic Characterization of Bloodstains Is it blood? From what species did it originate? If the blood is of human origin, how closely can it be associated to a particular individual?
2009©Forensic Science Today Species Identification Prior to 1990, double immuno- diffusion plate was used for species identification of blood stains. Today scientists simply test using DNA techniques
2009©Forensic Science Today Techniques to Visualize Kastle-Meyer – uses H 2 O 2 + phenolphthalein to produce a bright pink color in the detection of peroxidase activity in blood Leucomalachite green. Leucomalacite green is dropped on the suspect stain. A positive blood result will immediately turn the swab greenish- blue.
2009©Forensic Science Today More Visualization Tetramethylbenzidine- test by placing drops on a suspect stain. A positive reaction is indicated by an intense blue color. Luminol- Luminol is also a field test that you may have seen on one of the forensic investigation television shows. It involves spraying the chemical onto the suspected bloodstain and viewing it in total darkness. If blood is present, it will begin to luminesce (glow a whitish-blue) within 5 seconds.
2009©Forensic Science Today Luminol Test Extremely Sensitive- capable of detecting bloodstains diluted up to 300,000 times Large areas are sprayed and viewed in darkened areas for emission of light Does not interfere with subsequent DNA testing Figure 12-5 p. 337 Saferstein Criminalistics, 2004
2009©Forensic Science Today A Bloody Knife from a Homicide Scene.
2009©Forensic Science Today From what species did it originate? Preciptin Test >Very sensitive >Requires only a small sample >Even dried bloodstains from years ago can be tested. >Positive test results even in diluted samples Gel diffusion See pp Saferstein, Criminalistics, 2004.
2009©Forensic Science Today Applications of Genotyping Blood Factors No direct relevance to Criminal Investigations Paternity Testing Blood type may clear a suspect Example: Child is type AB Mother is type AB Suspected Father is type O Draw the Punnett Square.
2009©Forensic Science Today Rape Statistics
2009©Forensic Science Today Forensic Characterization of Semen Locate the stain and screen for semen with the acid phosphatase color test Acid phosphatase is an enzyme present in high concentrations in semen Suspect stain is transferred to filter paper; reagent is added. If semen is present, sample will fluoresce under UV light within 30 seconds.
2009©Forensic Science Today Microscopic Examination Semen can be identified by the presence of 400x magnification
2009©Forensic Science Today Challenges for the Microscopist Sample collection: Sperm bind tightly to cloth materials, are extremely brittle when dry, and disintegrate if the stain is washed or rubbed against another object Oligospermia – abnormally low sperm count (prefix Oligo means “just a few or scant” Aspermia - absence of sperm or sterility (partly due to growing popularity of vasectomies)
2009©Forensic Science Today p30 or Prostate Specific Antigen Protein discovered in 1970’s Unique to seminal plasma See Criminalistics pp. 351 & 352 Figure 12-6 and Figure for PSA testing by precipitation and electrophoresis If semen is present, DNA testing is used to link seminal material to an individual. More later....
2009©Forensic Science Today Collection of Rape Evidence Forceful physical contact between victim and assailant may result in the transfer of hair, fibers, blood, and semen (Locard’s Exchange Principle) Carefully package all outer garments and undergarments separately in PAPER bags. Victim should stand on paper while undressing so that any loose fibers can be collected for analysis. Collect bedding, if appropriate
2009©Forensic Science Today Collection of Rape Evidence Disposable latex gloves are essential for handling evidence! DNA may be transferred through perspiration. Investigators must avoid direct personal contact with evidence.
2009©Forensic Science Today Victim needs a medical exam ASAP! Evidence collection kit includes Pubic combings & standard/reference samples External genital skin areas Vaginal swabs & smear Cervix swabs Rectal swabs & smear Oral swabs & smear Head hairs Blood sample Fingernail scrapings All clothing Urine specimen (for drug testing e.g. Rohypnol, GHB) Swab of any area that may have assailant’s saliva for DNA testing See Saferstein, Criminalistics, 2004, p. 353
2009©Forensic Science Today Evidence from Suspect, if apprehended All clothing Pubic Hair combings Pulled head and pubic hair standard/reference samples Penile swab taken within 24 hours after assault Blood sample or buccal swab for DNA testing
2009©Forensic Science Today DNA Testing Extremely sensitive- characterization possible with only 1 billionth of a gram of sample
2009©Forensic Science Today Timing SSperm can survive up to 4-6 hours in the vaginal cavity of a living female. Time of sexual attack may be determined. NNonmotile sperm may be found up to 3 days after intercourse. AAcid phosphatase can be detected in the vaginal cavity for up to 48 hours after intercourse. p30 can be detected for 24 hours.
8-1 PRENTICE HALL ©2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE An Introduction By Richard Saferstein FORENSIC SEROLOGY Chapter.
Forensic Science: An Introduction Blood and DNA. Blood Components Formed Elements (cells) – 45% –Erythrocytes - Red Blood Cells carry oxygen –Leukocytes.
Identification and Characterization of Blood and Bloodstains.
Serology. Objectives You will be able to: Determine whether a stain is blood. Determine whether a bloodstain is human or animal blood. Determine the blood.
Forensic Serology Chapter 12. Topics this Chapter: Blood typing –Class evidence (presumptive) DNA profiling (later chapter) –Individual evidence (confirmatory)
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The Crime Scene Chapter 2. Physical Evidence Encompasses any and all objects that can establish that a crime has been committed or can provide a link.
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Evidence Chapters 3 & 8. Types of Evidence 2 types exist Testimonial Physical.
Chapter 3 – Physical Evidence List the common types of physical evidence encountered at crime scenes List the common types of physical evidence encountered.
Problems in Crime labs Especially the Houston Police Department and Presenting DNA Evidence to a Jury Elizabeth A. Johnson, Ph.D.
ABTIBODY SCREENING Dr. Mohammed H Saiemaldahr BLOOD BANK MED TECH
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Forensic Science. Copyright © Texas Education Agency All rights reserved. Images and other multimedia content used with permission. Copyright and.
Casework Intelligence Major Crime Cases. General Information Before deciding the way forward in cases it is important to understand the background of.
Investigating the Crime Scene. First responder (usually a police officer) –Offers assistance to injured persons –Identifies witnesses and suspects –Identifies.
#1 Task Determine if there is physical evidence that connects the suspect to the crime.Determine if there is physical evidence that connects the suspect.
Tutorial - DNA Fingerprinting And Electrophoresis.
General Microbiology Lecture Twelve Identification of Bacteria.
The Blood Group Systems Inheritance and Genetics.
Blood Typing ABO. Blood: How much do we have? The average adult has about five liters of blood living inside of their body.
Introduction to Forensic Science and Criminalistics Prepared by Peter Bilous Eastern Washington University Chapter 10.
Applications of Biotechnological Processes Antibody Production.
Entomology. Introduction o Entomology is the study of insects o Forensic entomology is the study of the insects associated with a dead body o Also known.
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11-1 PRENTICE HALL ©2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE An Introduction By Richard Saferstein Trace Evidence ll:
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