Biometric modality: DNA – key considerations
DNA profiling to establish human identity uses material from the non-coding regions of the genome and therefore contains very little extra genetic information. Each individual has a different DNA profile except identical twins who share the same DNA. Consequently, most people can be identified by their DNA profile and close family members e.g. parents/children, siblings etc. can be linked to one another through inherited DNA information. However, information regarding other physical traits (phenotypes) are difficult to obtain from the non-coding regions and although research into extracting features such as hair/eye colour has met with some success it has not been possible, so far, to generate many other traits.
DNA, in common with fingerprints, is used extensively within law enforcement investigations and the DNA samples recovered from crime scenes may be degraded, contaminated or mixed (two or more profiles in one sample) and generate only a partial profile. A combination of specialist software and expert human interpretation is usually needed to interpret any resultant profiles and potential matches obtained from such material. This entire process would normally be governed by a Quality Management System operating to International Standards Organization (ISO) protocols. (Refer to the Biometrics Institute Good Practice Framework E.4.2 to see how the use of standards fits within the context of a complete biometric system).
Law enforcement DNA databases use the same permutation of searches as fingerprint databases i.e. the combinations of DNA profiles generated from those arrested/convicted of crimes and DNA profiles obtained from crime scene samples.
