ABO blood group system
Definition
Classification of red blood cells by the presence or absence of A and B antigens on the cell membrane, determined by alleles at the ABO locus on chromosome 9. ABO typing is a serological screening tool; it cannot individualize but can exclude a potential source. Secretor status determines whether ABO antigens are present in body fluids such as saliva and semen.
Related terms
- Mitochondrial DNA (mtDNA)
- DNA located in mitochondria rather than the cell nucleus. Present in hundreds to thousands of copies per cell, making it recoverable from...
- Degradation
- The breakdown of DNA by enzymatic, chemical, or physical processes after biological material is deposited. Degradation produces fragmented DNA that may not...
- Enzyme-linked immunosorbent assay (ELISA)
- An immunoassay format in which an enzyme-conjugated antibody produces a measurable colour change on substrate addition. Developed in 1971, adopted in forensic...
- Lateral-flow immunoassay
- A point-of-care competitive immunochromatographic format on a nitrocellulose strip. In the absence of drug, colloidal gold-labelled antibody is captured at a test...
- Leukocyte
- White blood cell. The forensically critical component of blood because it contains a nucleus with a full complement of genomic DNA. Leukocytes...
- Monoclonal antibody
- An antibody produced from a single B-cell clone, recognising a single specific epitope. In forensic species identification, monoclonal antibodies offer higher specificity...
- PCR (Polymerase Chain Reaction)
- A method for amplifying specific DNA sequences from very small or degraded samples, developed by Kary Mullis in 1983. PCR made DNA...
- Precipitin test
- A serological method in which an antiserum specific to one species' proteins is mixed with an extract of an unknown specimen. Formation...
- Presumptive test
- A fast, low-cost, class-specific screen used to triage a caseload before instrumental work begins. Examples are Marquis reagent for opioids and amphetamines,...
- Radioimmunoassay (RIA)
- An immunological quantification method developed in the late 1950s in which a radiolabelled antigen competes with unlabelled antigen for antibody binding sites....
- RFLP (restriction fragment length polymorphism)
- The first DNA profiling method used in forensic casework, developed by Alec Jeffreys in 1984. Restriction enzymes cut DNA at specific sequences,...
- Short tandem repeat (STR)
- Short repetitive DNA sequences scattered throughout the genome, with the number of repeats varying between individuals at each locus. DNA profiling compares...
Explained in these topics
- Blood as Biological EvidenceClassification of red blood cells by the presence or absence of A and B antigens on the cell membrane, determined by alleles at the ABO locus on chromosome 9....
- History and Development of Forensic BiologyA classification of human blood based on the presence or absence of A and B antigens on red blood cell surfaces, described by Karl Landsteiner in 1901. The fir...
- History of Forensic Serology and Immunological MethodsThe system of A and B antigens on red cell surfaces, described by Landsteiner in 1901 and typed by naturally occurring anti-A and anti-B antibodies. The first...