Forensic Biology by Richard Li Chapter 7: Species Identification Forensic Biology by Richard Li

General Considerations Species Identification: In the past, done by serological methods Now, accomplished by DNA quantitation Can be a good screening method for unnecessary tests Can be used at the crime scene Necessary in animal cases Use primary and secondary binding assays Forensic Biology by Richard Li

Types of Antibodies Antihuman serum Albumin Hemoglobin antibody Glycophorin A Forensic Biology by Richard Li

Titration of Antibodies Series of dilutions of antiserum are made and each dilution is then tested for activity using either precipitation or agglutination methods Titer- the reciprocal of the highest dilution giving a positive reaction. Forensic Biology by Richard Li

Specificity Most antihuman sera usually have cross-reactivity with higher primates Crimes involving primates are rare Forensic Biology by Richard Li

Optimal Conditions Proper buffer system Ionic strength Intro of polymers Temperature pH Forensic Biology by Richard Li

Assays Immunochromatographic Assays Identification of human hemoglobin protein Hexagon OBTI ABAcard HemaTrace Identification of human glycophorin A protein RSID-Blood Forensic Biology by Richard Li

Assays Precipitation-based assays Ring assay Ouchterlony assay Identity Non-identity Partial identity Crossed-over electrophoresis Forensic Biology by Richard Li