Forensic Biology by Richard Li - Fayetteville State University

Chapter 10: Blood Group Typing and Protein Profiling Antigen polymorphisms that are present on the erythrocyte surface 29 blood group systems E.g. Rh, MNSs, Kell, ABO ABO system is the most commonly used in forensics

Forensic Biology by Richard Li 2 ABO System A, B, AB, O Type A: have A antigen Type B: have B antigen Type AB: both A and B antigens Type O: neither A nor B antigens

Found in many tissues other than blood Forensic Biology by Richard Li 3 O Antigen (H antigen): generated by all Fucosyltransferase Galactosyltransferase

Forensic Biology by Richard Li 4 Secretors A, B, O antigens are widely distributed in other tissues Approx. 75% of Caucasians Nonsecretors Homozygous for a nonsense mutation in FUT2 resulting in a truncated protein

Approx. 20% of Caucasians Forensic Biology by Richard Li 5 Individuals Probability divided into four groups of two randomly chosen individuals will be identical for a known blood type is high Can exclude suspects

Forensic Biology by Richard Li 6 Agglutination Assays Lattes Crust Assay Absorption-Elution Assay Forensic Biology by Richard Li

7 Developed due to limitations with blood group typing Inherited protein polymorphic markers 20-30% of proteins in humans are polymorphic Identification: Electrophoretic separation based on

molecular weight and the charge of the protein variants Forensic Biology by Richard Li 8 More than 200 Hb variants identified Useful markers Fetal Hb E.g. Infanticide

Hemoglobin S Investigative leads for indication of ethnic origin Forensic Biology by Richard Li 9