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Forensic BiologyRichard Li, with additions and edits by Ruth Ballard
Lecture 1: Forensic Biology: A Sub-discipline of Forensic Science
Outline
About your professor Class and Individual characteristics
About this courseCreating a Crime MapWhat is forensic science?Forensic laboratory servicesWhat is forensic biology?History of forensic biology: 1960-
present2
Name: Ballard, RuthHair: BrownEyes: GreenHt: 5’ 2”Wt: 105Occupation: Professor and researcherLast Known Address:Dept of Biological SciencesCalifornia State University, Sacramento
About your Professor
5
Identifying Characteristic: DNA profile
You’d need to te
st 100 billi
on earth’s w
orth of p
eople to fin
d another p
erson w
ith D
r. Balla
rd’s pro
file!
About this course
6
DNA breakthroughs in 1990s
+
News coverage
= BIO 150
Naïve new professor
Students watching TV shows
+TV
shows
+
+
Creating a Crime Map
A Crime Map is a visual summary of a crime Becomes a tool for remembering how
everything fits together Helps put biological evidence in context as
you receive it Can be organized in many different
ways This is your opportunity to be creative!
▪ Colored pencils, flow charts, time-lines Submit one per lab pair
7
Creating a Crime Map
At a minimum should include:Basic information about the crime
▪ Date, time, location▪ Victims▪ Suspect (if identified)▪ Eyewitness reports (to establish probable scenarios)
Evidence collected ▪ When/where/by whom▪ Where it is being stored
Pending or completed analyses by other units What’s available for testing and what’s
missing8
Creating a Crime Map
Example on the board You can continue to update your crime map
as the semester progresses Add results of your own lab analyses
Due for grading in lab on week from this coming Friday This week in lab: Introduction Next week in lab: Lab 1 (The Crime Scene:
Setting, Evidence, and Process); Crime map due Use supplementary materials at back of lab
manual as your source of information for the map
9
What is Forensic Science?
Forensic Science is the application of science to matters of Law.
Is uniquely cross-disciplinary and draws upon: Chemistry (Is this white power cocaine?) Biology (Did the semen come from the suspect?) Physics (How fast was the car going at impact?) Anthropology (Are these bones human?) Medicine (How did this child die?)
10
“Matters of Law” include: Crimes
▪ Homicide, sexual assault, burglary, etc. Disputes among individuals
▪ Wrongful death, patents, etc. Establishing rights
▪ Parentage; immigration, land disputes Investigation of disasters
▪ Natural and man-made
11
What is Forensic Science?
Unique roles of forensic scientists: Assist in recognition and collection of
physical evidence Document and maintain chain-of-
custody Analyze and evaluate the evidence using
a variety of scientific approaches Interact with the legal system
▪ Assist attorneys (and often law enforcement personnel)
▪ Testify in Court 16
What is Forensic Science?
NOT a branch of Law Enforcement! Forensic scientists do not interrogate
and arrest suspects Forensic scientists do not usually
investigate crimes▪ Crime Scene units of law enforcement
agencies and forensic medical professionals collect most of the evidence
▪ Evidence from the crime scene is then sent to forensic scientists at crime labs for analysis
18
What is Forensic Science?
Forensic Laboratory Services
19
Lab Director
Administration
Biology Criminalistics Chemistry Toxicology Quality Assurance
Comparative Evidence
Trace Evidence
Arson
Controlled Substances
Clandestine Labs
Toxicology
Alcohol
Organization of Sacramento County Crime Lab
Also see Table 1.1 in textbook
Forensic Laboratory Services
Most crime labs in U.S. are public sector laboratories available only to law enforcement and prosecutors 30 public crime labs
11 California Department of Justice 9 County Sheriff’s Crime Labs 7 City Police Department Crime Labs 3 County District Attorney Crime Labs
20
Forensic Laboratory Services California Dept of Justice crime labs:
Sacramento Ripon Watsonville Richmond (does the most hiring in California) Santa Barbara Chico Fresno Riverside Santa Rosa Eureka Redding
21
YOU DO NOT NEED TO MEMORIZE THESE!
Forensic Laboratory Services
County Sheriff’s Dept crime labs in California: Alameda County (San Leandro) Fresno County (Fresno) Contra Costa County (Martinez) Los Angeles County (Los Angeles) Orange County (Santa Ana) San Bernardino County (Rancho Cucamonga) San Mateo County (San Mateo) San Diego County (San Diego) Ventura County (Ventura)
22
Forensic Laboratory Services
County District Attorney crime labs in California: Sacramento County (Sacramento) Kern County (Bakersfield) Santa Clara County (San Jose)
23
Forensic Laboratory Services
City Police Dept crime labs in California: El Cajon Los Angeles San Francisco Huntington Beach Oakland Long Beach San Diego
24
Forensic Laboratory Services There are also private forensic
laboratories Independently test forensic evidence Available to defense attorneys and their
clients as well as the general public 16 private labs in California including
SERI (Richmond CA) Forensic Analytical (Hayward CA) Forensic Laboratory Services (San Luis Obispo) Forensic DNA Consulting (Mountain View)
25
Forensic Laboratory Services
28
Gas chromatography-mass spectrometerWhich unit of a crime lab would have this?
Forensic Laboratory Services
29
Capillary electrophoresis unit for Forensic DNA profilingWhich unit of a crime lab would have this?
Forensic Laboratory Services
30
Tissue samples from a deceased person, suspect, or crime victim.Which unit of a crime lab would process these and for what purpose?
Forensic Laboratory Services
31
A comparison microscope for ballistic analysis.Which unit of a crime lab would have this?
Forensic Laboratory Services
32
Scanning electron microscope used in gunshot residue analysis.Which unit of a crime lab would have this?
What is Forensic Biology?
Broad Definition: The application of the theory and practice of any branch of the biological sciences to matters of law Pathology (anatomy and physiology) Entomology (invertebrate zoology;
insects) Odontology (dentistry) Physical anthropology (study of bones) Microbiology, botany, wildlife… Body fluids (serology) and DNA
33
What is Forensic Biology?
Forensic Pathology Autopsies used to determine:
▪ Cause of death▪ Manner of death:
▪ Natural▪ Homicide▪ Suicide▪ Accident▪ Undetermined
34
What is Forensic Biology?
Forensic Entomology The study of insects in relation to a
criminal investigation Estimating time of death
▪ Stages of insect development
36
After death, blow flies infest
dead bodies
What is Forensic Biology?Forensic Odontology
Use characteristics of teeth, alignment, and overall structure
Bite mark analysis Useful in the identification of victims
whose bodies are unrecognizable Most people have dental records Dentition and dental history are unique
to each person
37
What is Forensic Biology?Narrow Definition: The
application of serological and DNA testing in matters of Law.
Goal is to generate identifying information from biological evidence: DNA Forensic serology
▪ Finding/identifying biological stains and materials
Forensic DNA analysis▪ Generating DNA profiles from biological
stains/materials39
What is Forensic Biology?DNA used to:
Link suspect to crime scene Link victim to crime scene Link suspect to victim Link victim to suspect Link multiple crimes to a single suspect
We’ll learn more about how cells (and DNA) are transferred in Lecture 2
40
History of Forensic Biology
Two trends: Dramatically increased level of
probability that a suspect is the source of a crime scene sample (16 orders of magnitude)
Dramatically fewer numbers of cells need for testing▪ Ability to generated DNA profiles from “trace
evidence,” including “contact DNA”
41
Important Definitions
Random match probability = RMP Probability of randomly selecting an
individual from the population with the same combination of biological markers as the evidence sample
Power of discrimination = PD = 1/RMP
42
History of Forensic Biology
Began with discovery of red blood cell surface antigen polymorphisms 1900 Karl Landsteiner discovered ABO
blood group antigens Developed by Lattes into ABO blood
typing Immediate applications in medicine
(transfusions) First applied to forensic casework in
1960s43
History of Forensic Biology
Limitations: Not very sensitive (lots of cells needed) Sample must be fresh Non-secretors RMP high; PD low
▪ 49% of Americans have blood type O▪ RMP ~ 0.25 (1 in 4); DP = 4
44
History of Forensic Biology
Blood protein markersBy 1980 approximately 100 had
been discovered Several used by forensic biologists Combined with ABO antigen system
▪ RMP ~0.001(1 in 1000)▪ PD = 1000
Same limitations as the ABO system but higher PD
45
History of Forensic BiologyDNA Fingerprinting
1984 Sir Alec Jeffreys ▪ Used in 1986 to solve murder case in the
United Kingdom (The Blooding) High PD (~109) Still required a large, fresh sample
Large visible blood stain Rape with ejaculation taken soon after crime
46
Forensic Biology
Huge breakthrough in 1986: PCR Polymerase chain reaction Allowed “amplification” of low-level DNA
prior to analysis A hundred cells rather than hundreds of
thousands▪ Human cell contains 6 pg DNA▪ DNA fingerprinting: 1 ug needed = 167,000
cells▪ PCR: 100 pg needed = 17 cells
47