Chapter 16: Detection Methods

 Agarose Gels  Ethidium Bromide ▪ Amounts as little as 10 ng per band ▪ Including in the gel OR staining after electrophoresis ▪ UV transilluminator at approx. 300nm & orange filter  Denatured Polyacrylmide Gels  Silver Nitrate ▪ 100x more sensitive, lower cost, safer Forensic Biology by Richard Li2

 Radioisotope Labeled Probes  VNTR testing & DNA quantification  Nick translation- dNTPs  Dnase I  P- most common radioisotope  Enzyme Conjugated Probes with Chemiluminescence Reporting System  Alkaline Phosphatase ▪ Lumigen PPD Forensic Biology by Richard Li3

 Biotin  Vitamin H found in egg yolk  Enzyme Conjugated Avidin  Glycoprotein found in egg whites  Binds to Biotin  Streptavidin  Horseradish peroxidase- contains Heme Forensic Biology by Richard Li4

 Reporter Enzyme Assay  TMB- chromogenic substrate  Luminol-chemiluminescent substrate Forensic Biology by Richard Li5

 Fluorescence Labeling  Dyes  nm  Labeling Methods  Primer method for STR (one primer)  Fluorescently labeled ddNTPs  Fluorophore Detection  Laser utilized as excitation source  Optical filters used to detect emitted light  Detector Forensic Biology by Richard Li6