Forensic Identification: Dactylography
The Science of Fingerprint Identification
Dactylography (or dactyloscopy) is the study of fingerprints for identification. It is considered the most reliable method of identification in forensic science due to the biological permanence and individuality of the patterns.
1. Galton’s Principles
Fingerprint science is based on three foundational principles:
- Permanence: Friction ridge patterns are formed during fetal development (around the 3rd–4th month) and remain unchanged throughout life.
- Uniqueness: No two individuals (even identical twins) have the same fingerprint pattern.
- Invariability: Patterns are constant; if the skin is damaged, the pattern regenerates exactly as it was.
2. Henry Classification System
| Pattern Type | Frequency (Approx) |
|---|---|
| Loops | 60–65% (Most common) |
| Whorls | 30–35% |
| Arches | 5% (Rarest) |
3. NEET PG High-Yield Pearls
- Minutiae (Galton Details): These are the specific ridge characteristics (bifurcation, ridge ending, dots, islands) used for comparison. 12 to 16 matching points are generally required for legal identification.
- Latent Prints: Invisible prints left by sweat, oils, or secretions; require developing agents (powders, fumes like Cyanoacrylate/superglue).
- Poroscopy: The study of sweat pores. In cases where ridge patterns are unclear, the number and arrangement of pores can be used for identification.
- Edgeoscopy: The study of the shape and contour of the edges of the friction ridges.
- Medical Condition: Certain conditions, like Adermatoglyphia (absence of fingerprints), are rare genetic markers.