Forensic DNA Typing: Quo Vadis?

Abstract

Since Alec Jeffreys coined the term "individual-specific genetic fingerprints" in 1985, DNA typing has become indispensable in forensic analysis, having as its central rationale the evidential power of the "match" between trace evi- dence and suspect. Established technological advances in this field include the adoption of the polymerase chain reaction (PCR) to generate DNA profiles from minute biological samples, the use of mitochondrial DNA to obtain information from old bones and the application of Y chromosomal polymorphisms in sexual assault cases. Present research questions focus on genetic markers for external visible traits and on improving the utility of poor quality samples with degraded DNA. The first valid marker for a physical trait was the sex marker amelogenin, which has been part of short tandem repeat (STR) multiplex PCRs for over a decade. Current studies are investigating markers for human pigmen- tation, predicting hair, iris and skin colour. The relationship between genome and pigmentation however is complex, involving numerous genes. Single nucleotide polymorphisms (SNPs) in these genes make promising candidates for predictive markers. Physical stature is also a complex genetic trait where study subjects can be phenotyped easily. Linkage analy- sis has revealed several short stature-quantitative trait loci, and polymorphisms in the fibrillin I gene are asso- ciated with tall stature.