Spermatozoa
Definition
Mature male gametes. Microscopic identification of intact spermatozoa with the characteristic head, midpiece and tail is the gold-standard confirmatory for semen in non-azoospermic donors.
- Field
- Forensic serology
- Definition
- Mature male gametes
- Identifying structure
- Head, midpiece, tail
- Evidentiary status
- Gold-standard confirmatory for semen in non-azoospermic donors
Common questions
Why does spermatozoa identification not work for every semen donor?+
Vasectomised or azoospermic individuals produce seminal fluid with few or no sperm cells, so absence of spermatozoa in a stain does not rule out semen and other markers such as prostate-specific antigen are used instead.
How does age of a stain affect finding intact spermatozoa?+
Sperm tails degrade faster than heads with time, environmental exposure, and laundering, so an older or washed stain may show only detached heads or none at all even though semen was originally present.
Related terms
- Acid Phosphatase (AP)
- An enzyme present at high concentrations in seminal plasma. The Brentamine Fast Violet B (or SERI AP) spray test detects acid phosphatase...
- Alpha-Amylase
- Salivary enzyme. Detected by starch-iodine (clear zone in blue background) or the Phadebas reagent (blue colour from dye-linked starch). Concentration in saliva...
- Barberio Test
- Presumptive semen test. Saturated picric acid reacts with spermine to form yellow rhombic spermine picrate crystals.
- Florence Test
- Presumptive semen test. Iodine plus potassium iodide reacts with choline in semen to form dark-brown rhombic / needle-shaped choline iodide crystals.
- Hp, Gc, Tf
- The classical serum-protein polymorphism panel: haptoglobin (binds free haemoglobin; Hp1-1, Hp2-1, Hp2-2 phenotypes), group-specific component (vitamin D binding protein, Gc1F / Gc1S...
- Isoenzyme / Polymorphism
- Different molecular forms of the same enzyme separable by electrophoresis. Forensic polymorphic markers have several common alleles in the population, so a...
- P30 (PSA)
- Prostate-specific antigen, a glycoprotein secreted by the male prostate gland and present in semen at high concentrations. ELISA or lateral-flow immunochromatographic tests...
- PGM, EsD, AK, GLO
- The classical RBC isoenzyme panel: phosphoglucomutase, esterase D, adenylate kinase, glyoxalase I. All polymorphic, all typed by starch-gel or isoelectric-focusing electrophoresis of...
- Secretor
- An individual whose ABO blood group antigens are expressed on red blood cells and also released into body fluids such as saliva,...