1. Chapter 12: DNA Extraction

2.  Vary according to type of biological evidence  Method of choice= yields sufficient quantity, good quality, and high purity of DNA  Insufficient quantity  Poor quality  Low purity  Most common methods involve isolating total cellular DNA Forensic Biology by Richard Li2 Failure to obtain profile or partial profile

3.  Components:  Cell & Tissue Disruption  Lysis of Membranes & Organelles  Removal of Proteins & Cytoplasmic Contaminants  Contamination  Storage Forensic Biology by Richard Li3

4.  Cell & Tissue Disruption  Proteinase K  Boiling  Alkali treatment Forensic Biology by Richard Li4

5.  Lysis of Membranes & Organelles  Detergents  Buffer  High Salt concentrations  Reducing agents  Chelating agents Forensic Biology by Richard Li5

6.  Contamination  Introduction of exogenous DNA  Person and sample  Sample to sample  Samples and amplified DNA  Material from other organisms  Reagent blanks  Process separately  Use approved procedures Forensic Biology by Richard Li6

7.  Extraction with Phenol-Chloroform  Organic extraction  Extraction by Boiling Lysis & Chelating Agent  Chelex extraction method  Silica-based DNA Extraction  Chaotropic salts  Differential Extraction  Sexual assault cases Forensic Biology by Richard Li7