Forensic DNA Phenotyping (FDP)
Definition
Prediction of externally visible characteristics, ancestry and age of an unknown donor from SNP genotypes. Investigative lead, not identification.
- Input
- SNP genotypes from an unknown DNA donor
- Predicts
- Externally visible traits, ancestry, and age
- Evidentiary status
- Investigative lead only, not an identification
- Distinct from
- STR profiling used for individual identification
Common questions
Why can't FDP results identify a specific suspect on their own?+
FDP produces probabilistic predictions about traits such as eye colour, hair colour or ancestry across a population, not a unique genetic fingerprint, so it narrows the pool of possible suspects rather than confirming any one individual's identity.
How does an investigator actually use an FDP prediction?+
The predicted traits are combined with other case information to prioritise leads, for example focusing canvassing or witness questioning on individuals matching a predicted ancestry or eye colour profile, rather than being presented in court as a match.
Related terms
- Biogeographic Ancestry Inference (BGA)
- Statistical assignment of a donor to continental ancestry groups using Ancestry-Informative SNPs (AIMs). Distinct from racial categorisation.
- Body-Fluid-Specific Transcripts
- RNA markers expressed only in one fluid: HBB for blood, STATH for saliva, PRM1 for semen, MUC4 for vaginal fluid, MMP7 for...
- Deconvolution
- A computational technique that estimates the PSF and inverts its effect to recover a sharper image. The quality depends entirely on how...
- Externally Visible Characteristics (EVCs)
- Traits a witness could see: eye, hair, skin colour, freckling, hair shape, height. The EU-funded VISAGE consortium targets this set.
- HIrisPlex-S
- A 41-SNP externally visible characteristics (EVC) panel for simultaneous prediction of eye, hair, and skin colour, developed at Erasmus MC Rotterdam by...
- mRNA / miRNA
- Messenger and micro RNA. Forensic RNA profiling uses tissue-specific transcripts of both classes to identify body fluids.
- Parabon Snapshot
- A commercial DNA phenotyping service (Parabon NanoLabs, Virginia, US) that genotypes thousands of SNPs from a crime-scene sample and uses machine learning...
- SNP
- Single Nucleotide Polymorphism. A one-base variant at a defined position. FDP uses SNP panels, not STRs.