1. CHAPTER 13 DNA: The Indispensable Forensic Science Tool
Cameron Waldron
Forensics

2. What is DNA DNA= Deoxyribonucleic acid Parts of DNA
The molecules carry the body’s genetic information
Parts of DNA
Chromosomes- strands of genetic material
Genes- arranged along the chromosomes like beads on a thread

3. DNA at Work Traits controlled by DNA come from proteins.
A protein comes from a link of amino acids (the building blocks of proteins)
There are 23 pairs of chromosomes

4. Replication of DNA
It begins with the unwinding of the strands in the double helix
PCR (polymerase chain reaction)
Pieces of DNA can be copied with the aid of a DNA polymerase

5. Recombinant DNA: Cutting and Splicing DNA
Genetic code- the relationship between the base letters on a DNA strand and the type of protein specified for manufacture by the sequence of these letters
Restriction enzymes- chemicals that act as scissors to cut DNA molecules at specific locations

6. DNA Typing Restriction Fragment Length Polymorphisms
Tandem Repeats- region of a chromosome that contains multiple copies of a core DNA sequence that are arranged in a repeating fashion
Restriction Fragment Length Polymorphisms (RFLPs)- repeat segments cut out of the DNA double helix by a restriction enzyme

7. DNA RFLP process DNA is cut into fragments
Fragments are separated into bands by electrophoresis
DNA band pattern is transferred to a nylon membrane
Membrane with DNA fragments positioned exactly
Radioactive DNA probe is added
X-ray film placed next to the membrane to detect the pattern
Developed X-ray film showing DNA fragment that combined with radioactive probe

8. Polymerase Chain Reaction
Primer- short strand of DNA used to target a region of DNA for replication by PCR
Steps of the PCR process
Heat the DNA strands to about 94 degrees
Add the primers to the separated strands
Add the DNA polymerase and a mixture of free nucleotides to the separated strands

9. Short Tandem Repeats The latest method of DNA typing is STR
STRs are locations on the chromosome that contain short sequence elements that repeat themselves within the DNA molecule
Multiplexing- simultaneously detects more than one DNA marker in a single analysis

10. Mitochondrial DNA
Mitochondria are cell structures found in all of our cells
Sequencing is a procedure used to determine the order of the base pairs that comprise DNA

11. Combined DNA Index System (CODIS)
CODIS is a computer software program developed by the FBI
It lets crime labs to compare DNA profiles electronically

12. Collection and Preservation of Biological Evidence for DNA Analysis
Picogram- one trillionth of a gram
Low Copy Number- fewer than 36 DNA bearing cells
Epithelial Cells- The outer layer of skin cells
Substrate Control- An unstained object adjacent to an area upon which biological material has been deposited