Definition: DNA fingerprinting is a technique of identification based on the analysis of highly variable regions of DNA that are unique to every individual except monozygotic (identical) twins.
Principle
Every individual possesses a unique DNA pattern. DNA contains coding and non-coding regions; the non-coding regions contain highly variable sequences known as:
- VNTRs (Variable Number Tandem Repeats)
- STRs (Short Tandem Repeats)
Comparison of these polymorphic regions allows identification of a person with a very high degree of accuracy.
Specimens collected
| From living persons | From dead bodies | From crime scene |
|---|---|---|
| Peripheral blood | Blood | Blood stains |
| Buccal (cheek) swab | Teeth | Semen stains |
| Saliva | Bones (especially femur) | Saliva stains |
| Hair with root | Hair roots | Hair with roots |
| Semen | Muscle tissue | Bone fragments / teeth |
| Tissue biopsy | Internal organs | Tissue fragments |