DNA Typing, Fingerprinting, and Forensic Anthropology 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

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

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

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

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

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

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

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

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

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

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

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)

Three Basic Shapes Arch Loop Whorl *See handout*

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

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

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.

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

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

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