Forensic Medicine

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 persons occupation may have been
• When done, we will discuss as a group