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DNA Extraction Makeups Tuesday – after school 2:20 sharp!

DNA Extraction Makeups Tuesday – after school 2:20 sharp! . The Gold Standard of Forensic E vidence: DNA. By Sanford Herzon DNA Resource Center Montgomery County Public Schools Rockville, Maryland. Escaping the cell How it started The technology The chain reaction The law

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DNA Extraction Makeups Tuesday – after school 2:20 sharp!

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  1. DNA Extraction MakeupsTuesday – after school 2:20 sharp!

  2. The Gold Standard of Forensic Evidence: DNA By Sanford Herzon DNA Resource Center Montgomery County Public Schools Rockville, Maryland

  3. Escaping the cell • How it started • The technology • The chain reaction • The law • The ethical issues

  4. Escaping the cell • The Gold Standard • DNA Terminology • DNA Structure • DNA Extraction

  5. Federal Bureau of Investigation, 1997

  6. $5,000 for 200 rxns

  7. CSI: NIST

  8. “DNA has become the gold standard in the identification process” - Mike Coble when asked how DNA compares to other forensic evidence such as serology and fingerprints.

  9. Terminology • A chromosome is made of a DNA molecule. Humans have 46 chromosome in all body cells. • 46 chromosomes contains 3 billion codes (nitrogenous bases) of genetic information • A sequence refers a string of bases such as: ACTGCTC • A gene is a subunit of a chromosome. A gene codes for a specific trait like hair color or height.

  10. Terminology • Nuclear DNA – this refers to the 46 linear chromosomes found in the nucleus. Each parent contributes 23 chromosome to the offspring. • Mitochondrial DNA – one circular chromosome containing 37 genes. 13 of these genes are used in aerobic respiration to produce ATP (energy).

  11. Structure • Deoxyribonucleic acid • Molecule is referred to as “double helix” • Organic polymer made of repeating units called Nucleotides • 4. Nucleotides have 3 parts • 1. sugar – deoxyribose • 2. phosphate • 3. Nitrogenous bases • Adenine pairs with Thymine • Cytosine pairs with Guanine

  12. The Nucleotide

  13. DNA Extraction • Recipe for extracting DNA was discovered by Friedrich Meischer in 1869. • Today, most recipes involve four steps: • Centrifuge • Addition of lysis buffer • Addition of Salt solution • Addition of ethanol

  14. How WHS Agents Did it!

  15. Pellet the nuclei Ca++ Added Prep Buffer Added EDTA Mg++ Disorients phospholipids to breakdown nuclear membrane freeing the DNA Add SDS

  16. Add NaCl Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+

  17. Add EtOH

  18. Virtual Extraction Quiz– Due by Thursday, Dec. 19

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