Low copy number
Low Copy Number (LCN) is a DNA profiling technique developed by the Forensic Science Service (FSS) and in use in some countries since 1999.
In the United Kingdom use of the technique was suspended between 21 December 2007 and 14 January 2008 while the Crown Prosecution Service conducted a review into its use - this suspension has now been lifted.[1]
LCN is an extension of Second Generation Multiplex Plus (SGM Plus) profiling technique. It is a more sensitive technique because it involves a greater amount of copying from a smaller amount of starting material, meaning that a profile can be attained from only a few cells, which may be as small as a millionth the size of a grain of salt, and amount to a just few cells of skin or sweat left from a fingerprint.[2]
Successes
LCN evidence has allowed convictions to be made in several cold cases. For example, Mark Henson was convicted of rape in 2005, 10 years after the crime was committed, from re-analysis of a microscope slide. In 1981, evidence was deliberately kept after the rape and murder of 14 year old Marion Crofts. In 1999, a DNA profile was attained from this using LCN. This was continually checked against the UK National DNA Database for the next two years, until a match was eventually found for Tony Jasinskyj after he was arrested for another crime. He was eventually given a life sentence in 2002.[3]
So far the technique is only used in several countries:the UK, the Netherlands and New Zealand.
Criticism
It has been used in more than 21,000 serious crime cases in the UK and internationally, particularly in "cold" cases. A FSS spokesperson said: "LCN DNA analysis is only carried out by the most-experienced DNA scientists, who have undergone special additional training and testing in this area of casework." Howeveer, the technique came under attack from the Judge during the trail of Sean Hoey - who was eventually cleared of involvement in the Omagh Bombing. One of the criticisms the judge leveled at LCN was that although the FSS had internally validated and published scientific papers on the technique, there was an alleged lack of external validation by the wider scientific community.[4] Following the Judge's ruling, the use of the technique was suspended in the UK, pending a review by the Crown Prosecution Service. This review was completed and the suspension lifted on the 14 January 2008.[1]
"The CPS has not seen anything to suggest that any current problems exist with LCN"