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Forensic Medicine

Forensic Medicine. DNA Typing, Fingerprinting, and Forensic Anthropology. DNA Typing. What is DNA? Nucleus of cells contain RNA/DNA DNA: deoxyribonucleic acid Nucleus has 23 pairs of chromosomes made up of DNA Within each pair, there is one chromosome from sperm and one from the egg .

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Forensic Medicine

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  1. Forensic Medicine DNA Typing, Fingerprinting, and Forensic Anthropology

  2. DNA Typing • What is DNA? • Nucleus of cells contain RNA/DNA • DNA: deoxyribonucleic acid • Nucleus has 23 pairs of chromosomes made up of DNA • Within each pair, there is one chromosome from sperm and one from the egg

  3. What makes DNA individual? • Four chemicals: adenine, guanine, cytosine, and thymine • Chemical strung together = DNA code • Some sections of DNA vary from individual to individual • Scientists can link a strand of DNA to a given individual

  4. Criminal Investigations • DNA specimens: blood, hair, bodily secretions (sweat, semen, vagina), bloodstained clothing • Provides powerfully compelling evidence • Has even proven innocence

  5. Fingerprints • No other technique of identification can claim 100% reliability! • Infallible means of personal identification • Other personal characteristics can change, including DNA, fingerprints do not

  6. History of Fingerprints • Early civilizations used branding, maiming, or tattoo to identify thieves or deserters from the military • Thumb prints in clay were used to “seal the deal” in business transactions in Mesopotamia

  7. Hx • 1880: Dr. Henry Faulds, a British surgeon, noted patterns of fingerprints on pieces of prehistoric pottery. Research led to eventual credit of realizing its use in identification through his development of a fundamental classification system • 1892: Sir Francis Galton published the first book on technique that became the basis of modern fingerprinting science based on a 12 point system

  8. United States History • 1902: Fingerprints first used in the U.S. for Civil Service in NY • 1903: NY State Prison System for Criminals, followed by Feds • 1905: U.S. Army followed by the U.S. Navy • 1924: FBI fingerprint division • 1946: FBI had 100 million cards • 2004: 46 million computerized records for known criminals

  9. Scientific Facts • 1. They stay the same from fetal stage to sometime after death • 2. No 2 sets of fingerprints are alike, not even in identical twins

  10. Primary value in forensic science is to identify a person • Solving crimes by ID of victim or perpetrator • ID of persons for legal purposes (passports and licenses) • Access to secure areas

  11. Other areas with print patterns • Inside of fingers • Inside of hands • Bottom of feet and toes

  12. Two Types • 1. A positive print from stamping process • 2. A negative print from surface substance removal • All fingerprints have friction ridges (the lines) to prevents slipping when grasping

  13. Three Forms • 1. Visable: glass, leave a residue of fat, oil, or blood • 2. Impression: copper of silver; a chemical acid imprint • 3. Latent: invisible; requires a chemical reaction to visualize (cyanoacrylate fuming method) mixes with organic (amino and lactic acid) and inorganic (Na and K)

  14. Three Basic Shapes • Arch • Loop • Whorl • *See handout*

  15. Key Identity Markers • Typica (aka unique lines): • Endings • Splitting lines/bifurcations *See handout*

  16. Legal Identifying Markers “Points” • There are at least 150 individual ridge characteristics on the average fingerprint • If between 10 and 16 specific points of reference for any two corresponding fingerprints identically compare, a match is assumed • In a judicial proceeding, 12 corresponding points must match to identify a specific person

  17. Forensic Anthropology • The application of the science of physical anthropology to the identification of skeletal, badly decomposed, or otherwise unidentified human remains. • Apply standard scientific techniques developed in physical anthropology to identify human remains, and to assist in the detection of crime.

  18. Forensic Anthropology • Skeletal anatomy • 206 bones • Males have 12 pounds of bone on average • Females have 10 pounds on average • What bones show • How a person lived • Debilitation illnesses (rickets, polio, healed fractures) • Right-handed or left-handed • Clues to occupation

  19. Continued… • Questions about skeletal remains • Age of a person at time of death • Sex of person based on skull and pelvis • Race • Height

  20. Group activity • In groups of 3 or 4 discuss how a skeletal can show: • 1. How a person lived • 2. Illness a person may have had (fractures, polio, etc) • 3. If the person was right or left handed • 4. What the person’s occupation may have been • When done, we will discuss as a group

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