Forensic Biology by Richard Li - Fayetteville State University
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Transcript Forensic Biology by Richard Li - Fayetteville State University
Chapter 1: Forensic Biology
Common Disciplines:
Crime scene investigation
Latent print examination
Forensic Biology
Controlled substance analysis
Postmortem toxicology
Questioned document examination
Firearms, toolmark, and other impression evidence
examination
Explosives and fire debris examination
Transfer (Trace) evidence examination
Forensic Biology by Richard Li
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Forensic Pathology
Autopsies used to determine exact cause of death
Time of death
Manner of death:
▪ Natural
▪ Homicide
▪ Suicide
▪ Accident
▪ Undetermined
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Forensic Anthropology
Identification and examination of human skeletal
remains
Examination may reveal:
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Individual’s origin
Sex
Approximate age
Race
Presence of skeletal injuries
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Forensic Entomology
The study of insects in relation to a criminal
investigation
Estimating time of death
▪ Stages of insect development
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Forensic Odontology
Participate in the identification of victims whose
bodies are unrecognizable
Use characteristics of teeth, alignment, and
overall structure
Bite mark analysis
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History
Antigen polymorphism
Protein polymorphism
DNA polymorphism
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Antigen Polymorphism
1900 Karl Landsteiner discovered ABO blood
groups
A, B, AB, O
Forensic serology
Useful in excluding a suspect
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Protein polymorphism
By 1980 approximately 100 had been discovered
Combined with blood groups lowered the
probability of a match between two unrelated
individuals
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DNA polymorphism
1984 Sir Alec Jeffreys
▪ Variable Number Tandem Repeat (VNTR)
▪ Used in 1986 to solve murder case in the United
Kingdom
Able to reveal far greater individual variability
The probability of two unrelated individuals
having the same DNA profile is low
DNA from crime scene can be matched to a
suspect
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DNA polymorphism
Mid 1980’s Polymerase Chain Reaction (PCR)
technique
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Amplifies tiny quantities of DNA
Greatly increased the sensitivity of forensic DNA
Single Nucleotide Polymorphisms (SNP)
Amplified Length Polymorphisms (AFLP)
Short Tandem Repeat (STR)
▪ Greatly increased the sensitivity of the assay
▪ Highly variable
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DNA polymorphism
1995- First national DNA database for criminal investigations
established in the United Kingdom
1998- First in United States
▪ Combined DNA Index System (CODIS)
▪ 13 STR loci
Mitochondrial DNA (mtDNA)
▪ Maternally inherited
▪ Useful when nuclear DNA is degraded or in limited amounts
▪ E.g. shed hairs
Polymorphic markers at the Y chromosome
▪ Paternally inherited
▪ Paternity cases
▪ Multiple contributors in sexual assault cases
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