Chapter 1: Forensic Biology: A Subdiscipline of Forensic Science

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 Forensic Science is the application of science to matters of Law.  Is uniquely cross-disciplinary and draws upon:  Chemistry  Biology  Physics  Geology  Medicine 3

 “Matters of Law” include:  Crimes ▪ Homicide, sexual assault, burglary, etc.  Disputes among individuals ▪ Wrongful death, patents, family law, etc.  Establishing rights ▪ Immigration, land disputes  Investigation of disasters ▪ Natural and man-made 4

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8 Date:March 27, 1977 Location: Tenerife, Canary Islands Aircraft: Boeing B / Boeing B B Reg:N736PA/PH-BUF Airline: Pan American World Airways / KLM Flight No:1736 / 4805 Fatalities:644 : 583

'Baby 81' Reunited With Parents After DNA Tests End Agonizing Post-Tsunami Custody Dispute CBS/AP) "Baby 81," the infant claimed by nine couples after he miraculously survived the tsunami, was reunited with his parents Wednesday in the joyous conclusion to an agonizing custody battle that captured hearts around the world. Smiling with relief, Jenita Jeyarajah took the baby, dressed in blue, from a doctor's arms in a courtroom packed with onlookers after the judge said DNA tests confirmed the baby is her 4-month-old son Abilass.

DNA Science Matches Crash Victims With Families By MATTHEW PURDY Published: November 30, 1996

 Unique roles of forensic scientists:  Assist in recognition and collection of physical evidence  Analyze and evaluate the evidence using a variety of scientific approaches  Interact with the legal system ▪ Assist attorneys and law enforcement ▪ Testify in Court 11

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 Forensic Science is NOT a branch of Law Enforcement!  Forensic scientists do not interrogate and arrest suspects  Forensic scientists do not usually investigate crime scenes ▪ Crime Scene units of law enforcement agencies do most of the work of crime scene investigation ▪ Samples from the crime scene are sent to forensic scientists at crime labs for analysis 13

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 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 15Forensic Biology by Richard Li

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19Forensic Biology by Richard Li Lab Director Administration BiologyCriminalisticsChemistryToxicologyQuality Assurance Comparative Evidence Trace Evidence Arson Controlled Substances Clandestine Labs Toxicology Alcohol

 Most crime labs in U.S. are public sector laboratories operated and funded by the governments and jurisdictions they serve  California:  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 20Forensic Biology by Richard Li

 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

 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

 County District Attorney crime labs in California:  Sacramento County (Sacramento)  Kern County (Bakersfield)  Santa Clara County (San Jose) 23

 City Police Dept crime labs in California:  El Cajon  Los Angeles  San Francisco  Huntington Beach  Oakland  Long Beach  San Diego 24

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26 "Security" booth, Government Chemist Crime Lab, Nairobi Kenya (2010)

27 Gas chromatography-mass spectrometer Which unit of a crime lab would have this?

28 Capillary electrophoresis unit for Forensic DNA profiling Which unit of a crime lab would have this?

29 Tissue samples from a deceased person, suspect, or crime victim. Which unit of a crime lab would process these and for what purpose?

30 A comparison microscope for ballistic analysis. Which unit of a crime lab would have this?

31 Scanning electron microscope used in gunshot residue analysis. Which unit of a crime lab would have this?

 Forensic Pathology  Autopsies used to determine: ▪ Cause of death ▪ Time of death ▪ Manner of death: ▪ Natural ▪ Homicide ▪ Suicide ▪ Accident ▪ Undetermined 32

33 Forensic Pathology Facility. Run by Coroner’s or Medical Examiner’s Office

34 Histological specimens from an autopsy may be sent to a crime lab for toxicological testing.

 Forensic Anthropology  Identification and examination of human skeletal remains  Examination may reveal: ▪ Individual’s origin ▪ Sex ▪ Approximate age ▪ Race ▪ Presence of skeletal injuries 35

 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

 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

 In it’s broadest definition, is the application of the theory and practice of any branch of biological science in matters of law  Body fluid and DNA analysis (molecular biology)  Autopsy (anatomy and physiology)  Entomology (invertebrate zoology; insects)  Botany (plants)  Odontology (dentistry)  Physical anthropology (study of bones) 38

 In it’s more common, narrower definition, is the application of serological and DNA testing in matters of Law.  Includes:  Forensic serology ▪ Finding and identifying biological stains and materials  Forensic DNA analysis ▪ Generating DNA profiles from biological stains and materials 39

 Goal is to generate individual identifying characteristics from biological evidence:  Link suspect to crime scene  Link suspect to victim  Link multiple crimes to a single suspect  History:  Antigen polymorphism  Protein polymorphism  DNA polymorphism 40

 Antigen Polymorphism  1900 Karl Landsteiner discovered ABO blood group antigens: A, B, AB, O  Many other blood antigens discovered later; 29 systems now known  Discrimination low:  Non-secretors  Prone to degradation 41

 Protein polymorphism  By 1980 approximately 100 had been discovered  Combined with blood groups lowered the probability of a match between two unrelated individuals  Prone to degradation 42

 DNA polymorphism  1984 Sir Alec Jeffreys ▪ Variable Number Tandem Repeat (VNTR) ▪ Used in 1986 to solve murder case in the United Kingdom (The Blooding)  Able to reveal far greater individual variability  The probability of two unrelated individuals having the same DNA profile is low (10 -9 )  DNA from crime scene can be linked to a suspect with a high degree of certainty  Requires lots of cells to work  Does not work well on degraded DNA samples 43

 DNA polymorphism  Mid 1980’s Polymerase Chain Reaction (PCR) technique ▪ 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 ▪ Can match a suspect to crime scene with absolute certainty 44

 DNA polymorphism  First national DNA database for criminal investigations established in the United Kingdom  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 46