Application of DNA polymorphisms to individual identification

Objective: The objective of this review was to summarize application of DNA polymorphisms to individual identification. Design: A review of forensic medicine. Materials and Methods: As a powerful evidence, biological markers are not only widely used in criminal investigation, but also in clinical tissues identification such as pathological specimen mix-up as well as mass disasters and accidents such as airline crashes, train crashes, floods and building fires. While several methods are being used for human individual identification, the biological method is more important because the identification tests are not restricted to any particular or one body landmark. Furthermore, comparison of biological markers can be used to associate separated remains or body parts. Results: Polymerase chain reaction (PCR) commonly used in DNA polymorphisms has been developed to realize genetic analysis of multiplex loci employing fluorescent dye labeling technology. The genetic evidence provided by DNA polymorphic markers from the analyses of restriction fragment length polymorphisms (RFLPs), minisatellite (VNTR) polymorphisms, microsatellite (STR) polymorphisms, single nucleotide polymorphisms (SNPs) and mitochondrial DNA (mtDNA) has become the most powerful tool for individual identification in natural disasters and non-natural catastrophes, or criminal cases. Conclusion: DNA analysis is a highly discriminating tool that permits identification of remains, provided that a corresponding reference sample is available, either from biologically related family members or from the missing and unidentified person themselves. DNA markers have advantages over the traditional biological markers including the red blood cell group, serum protein types, isoenzyme types, HLA types and salivary protein types in several aspects: DNA markers are simply to analysis, require small amount of template for PCR amplification, can be used for the analysis of some degraded samples and have high power of discrimination. STR polymorphisms have become the major and widely used method for human identification tests both in criminal investigation and mass disaster victim identification.