Applied Genetics

Forensic Science Using science to help solve crimes

Examples of Forensic Science Forensic pathology Forensic dentistry Forensic anthropology Forensic entomology Forensic archaeology Forensic psychiatry Fingerprint analysis Forensic accounting

History of Forensic Science 1248 A Chinese book, Hsi Duan Yu (the washing away of wrongs), contains a description of how to distinguish drowning from strangulation. This was the first recorded application of medical knowledge to the solution of crime James Marsh, an Scottish chemist, was the first to use toxicology (arsenic detection) in a jury trial Odelbrecht first advocated the use of photography for the identification of criminals and the documentation of evidence and crime scenes Henry Faulds, a Scottish physician working in Tokyo, published a paper in the journal Nature suggesting that fingerprints at the scene of a crime could identify the offender.

History of Forensic Science 1905 American President Theodore Roosevelt established Federal Bureau of Investigation (FBI). (1977) The FBI introduced the beginnings of its Automated Fingerprint Identification System (AFIS) with the first computerized scans of fingerprints In the first use of DNA to solve a crime, Jeffreys used DNA profiling to identify Colin Pitchfork as the murderer of two young girls in the English Midlands. Significantly, in the course of the investigation, DNA was first used to exonerate an innocent suspect.

Tools of the forensic trade 1.) Restriction enzymes 2.) DNA polymorphisms 3.) Gel electrophoresis

1.) Restriction Enzymes Originally found in bacteria –Used for defense to destroy host cell’s DNA Cut up DNA at specific sites

ACGTACCGGTA TGCATGGCCAT Example: A restriction enzyme that cuts between ‘CC’ and ‘GG’

2.) DNA Polymorphisms Normal differences between the DNA sequences of individuals ACCTGGACCGGT TGGACCTGGCCA ACCCGGACGGGT TGGGCCTGCCCA

3.) Gel Electrophoresis DNA is pushed through a semisolid gel by a current. –DNA has a negative charge so it moves toward the positive end Smaller fragments move faster, larger fragments move slower. Fragments cut by restriction enzymes are sorted by length.

Today’s Case I found an IPOD in the classroom. Four students claimed it: DNA samples were taken from the 4 students. We will use restriction enzymes, DNA polymorphisms, and gel electrophoresis to determine who is telling the truth.

Questions 1.Whose IPOD is it? 2.Using scissors to cut up the DNA fragments was a way of simulating what tool of the forensic trade? 3.Taping the DNA fragments by length onto the chart you made was a way of simulating what tool of the forensic trade? 4.On your chart, label which side is positively charged (top or bottom?) and which side is negatively charged.

Gels for E. coliGels for E. coli OJ DNA

More Applied Genetics Cloning Genetic Manipulation –Mix ‘n match with genes

Cloning Why is cloning a sheep such a big deal?

Genetic Manipulation Examples –Medicines in milk –Antifreeze proteins –Glow in the dark pets Mr. Green Genes