Biological Forensics Laboratory Exercise 12

Forensics Lab Objectives  Learn the definition of forensic science.  Examine ways biological information can be used to solve crimes, and see examples of this in today’s society.

Forensic Science Definition: The application of the tools of science, as well as specific scientific facts, to help solve legal problems Goal: the determination of the cause, location, and time of death

Some Uses of Forensics Identify potential suspects whose DNA may match evidence left at crime scenes Exonerate persons wrongly accused of crimes Identify crime and catastrophe victims Establish timing and circumstances of a crime

Categories of Forensics DNA Evidence Forensic Entomology Forensic Serology Forensic Odontology Bluebottle blow fly

Fingerprint counting number of typica Forensic Fingerprinting Forensic Anthropology Forensic Art Radiocarbon dating of the Dead Sea Scrolls Composite art, image modification, age progression, post- mortem reconstruction and demonstrative evidence

Forensic Pathology Forensic Psychiatry Forensic Toxicology Bloodstain Pattern Analysis Forensic Photography

Biological Forensics Use of Entomology (the study of insects) Use of Molecular biology (DNA analysis)

Entomology  Use of the insects, and their arthropod relatives that inhabit decomposing remains to aid legal investigations  Compare the insect to the different stages of their life cycle

Common Insects Found on Carrion Blow Flies (order Diptera) Life cycle of a typical blowfly Some comon larvae or "maggots" found on human remains

Beetles (order Coleoptera) sexton beetle, Nicrophorus orbicollis American carrion beetle, Necrophila americana larvae shown here are from four different beetle families

Molecular Forensics  Use of identifying characteristics of molecules in our cells to aid legal investigations  Compare the DNA and/or blood type of crime scene evidence to that of suspects, or use this information to identify a victim.

Two main methods of Molecular Forensics PCR (Polymerase Chain Reaction) Blood typing

PCR (Polymerase Chain Reaction) –Developed in 1987 –Amplify one molecule of DNA into billions of copies in a few hours –Identifies an individual based on microscopic amount of evidence –99% accuracy rate

Genetic Variation Most genes have small sequence differences between individuals – Occur every 1350 bp on average Some of these polymorphisms may affect: – How well the protein works – How the protein interacts with another protein or substrate A gene is a unit of inheritance

Hydrogen Bonds H H H H O O H C C C C N N C Thymine H N H H N C C C C N N H N C Adenine H O N H C C C N N C Cytosine H H H N C C C C N N H N C Guanine N H O H

PCR DNA

Some Interesting Uses of DNA Forensic Identification ID 9/11 victims ID plane crash victims ID Missing children DNA Shoah Project Tomb of the Unknowns Son of Louis XVI and Marie Antoinette Nicholas Romanov Peruvian Ice Maiden African Lemba Tribesman Super Bowl XXXIV Footballs and 2000 Summer Olympic Souvenirs Study migration patterns Poached animals DNA banks for endangered species

Historical methods of identifying and individualizing blood and other body fluids Antigen-Antibody reactions Enzyme-Substrate reactions Forensic Serology

HISTORY In 1901 Dr. Karl Landsteiner discovered blood typing. awarded a Noble Prize.

White blood cells Platelets Red blood cells Artery

Plasma- 55% Formed elements- 45% Buffy coat- <1%

ANTIGENS

a a a a a a a a b b b b b b b b

AGGLUTINATION

Figure Serum Anti-A RBCs Anti-B Type AB (contains agglutinogens A and B; agglutinates with both sera) Blood being tested Type A (contains agglutinogen A; agglutinates with anti-A) Type B (contains agglutinogen B; agglutinates with anti-B) Type O (contains no agglutinogens; does not agglutinate with either serum)

Can this blood be associated to a particular individual? MAYBE!?!

Blood Type & RhHow Many Have ItFrequency ORh Positive1 person in 337.4% ORh Negative1 person in 156.6% ARh Positive1 person in 335.7% ARh Negative1 person in 166.3% BRh Positive1 person in 128.5% BRh Negative1 person in 671.5% ABRh Positive1 person in 293.4% ABRh Negative1 person in 167.6%

In Class Assignment Analyze 4 suspects blood types Compare it to blood found on the murder weapon. Determine the murderer.