DNA fingerprinting, which operates on the premise that every human's genetic make-up is unique, is the most significant advance in forensic science of the 20th century.
It is particularly useful in the investigation of murder and rape cases.
Each of our cells contains a copy of our entire genetic blueprint in the form of DNA (with the exception of sperm, egg and red blood cells).
Thus, a tiny specimen of hair or skin recovered from a crime scene can be used to identify a person.
A DNA fingerprint is the pattern produced after separating DNA fragments by the biochemical technique of gel electrophoresis.
The resultant fragments, which are in the form of lines of varying thickness, may be identified with an appropriate stain or DNA probe.
Depending on the source of the original DNA, the observed pattern may be unique to an individual organism.
Debate about the reliability of DNA fingerprinting centres around the possibility of human error, "false positives" and dispute over the reliability of the method. Notwithstanding the possibility of mistakes common to any criminal investigation, the technique has stood up to scrutiny - so much so that even old DNA samples have met the rigours of forensic science.
Ireland is behind other countries in using "intelligence policing" which includes widespread use of DNA databanks.
DNA profiles, for example, are kept of those who have been involved in crimes.
Some countries envisage profiling all its citizens to be in a position to quickly check suspects in major criminal investigations.
Irish legislation, as currently structured, is not amenable to the use of gene banks for such purposes.
But failure to fully adopt the technology, which can now work on smaller samples, down to the size of a tiny piece of dandruff, reduces the potential scope of investigations.
