1. Forensic Biology by Richard Li
Chapter 10: Blood Group Typing and Protein Profiling
Forensic Biology by Richard Li

2. Blood Groups
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

3. Blood Groups 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

4. Biosynthesis of Antigens
O Antigen (H antigen): generated by all
Fucosyltransferase
Galactosyltransferase
Forensic Biology by Richard Li

5. Secretors vs. Nonsecretors
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

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

7. Techniques for Blood Group Typing
Agglutination Assays
Lattes Crust Assay
Absorption-Elution Assay
Forensic Biology by Richard Li

8. Forensic Protein Profiling
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

9. Hemoglobin 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