STRprofiili

STRprofiili, or short tandem repeat profile, is a genetic profile produced by analyzing specific short tandem repeat loci in a person’s DNA. STRs are short sequences of DNA that repeat in tandem, and the number of repeats at each locus varies among individuals. This variability makes STRs highly informative for identifying individuals and determining relatedness.

To generate an STR profile, DNA is extracted and subjected to polymerase chain reaction (PCR) to amplify selected STR loci. The resulting fragments are separated by capillary electrophoresis and sized to determine the number of repeats at each locus. The observed alleles are recorded as numbers, forming a multi-locus genotype that constitutes the STR profile.

A typical STR profile covers a standardized set of loci; modern forensic panels include 15–20 loci, sometimes with additional markers. The profile can be matched against reference samples in a database or against a suspect’s sample. The strength of a match is quantified by statistical calculations, such as random match probability or likelihood ratios, which depend on allele frequencies in reference populations.

Applications include criminal investigations, paternity or kinship testing, and disaster victim identification. Quality considerations include mixed or degraded samples, partial STR profiles, and artifacts such as stutter. Reported results reflect laboratory methods, interpretation criteria, and the uncertainty inherent in the data. Legal and privacy issues govern the collection, storage, and sharing of STR profiles, with strict chain-of-custody and data protection requirements.