Low Copy Number (LCN) is a

DNA profiling DNA profiling (also called DNA fingerprinting) is the process of determining an individual's DNA characteristics. DNA analysis intended to identify a species, rather than an individual, is called DNA barcoding. DNA profiling is a forensic tec ...

technique developed by the UK

Forensic Science Service The Forensic Science Service (FSS) was a government-owned company in the United Kingdom which provided forensic science services to the police forces and government agencies of England and Wales, as well as other countries. The UK Government a ...

(FSS) which has been in use 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 The Crown Prosecution Service (CPS) is the principal public agency for conducting criminal prosecutions in England and Wales. It is headed by the Director of Public Prosecutions. The main responsibilities of the CPS are to provide legal adv ...

conducted a review into its use – this suspension has now been lifted.CPS Press Release : Review of the use of Low Copy Number DNA analysis in current cases: CPS statement
/ref> LCN is an extension of

Second Generation Multiplex Plus Second Generation Multiplex Plus (SGM Plus), is a DNA profiling system developed by Applied Biosystems. It is an updated version of Second Generation Multiplex. SGM Plus has been used by the UK National DNA Database since 1998. An SGM Plus profile ...

(SGM Plus) profiling technique. It is a more sensitive technique because it involves a greater amount of copying via

polymerase chain reaction The polymerase chain reaction (PCR) is a method widely used to rapidly make millions to billions of copies (complete or partial) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it (or a part of it) t ...

(PCR) from a smaller amount of starting material, meaning that a profile can be obtained from only a few cells, which may be as small as a millionth the size of a

grain of salt To take something with a "grain of salt" or "pinch of salt" is an English idiom that suggests to view something, specifically claims that may be misleading or unverified, with skepticism or to not interpret something literally. In the old-fa ...

, and amount to just a few cells of skin or sweat left from a fingerprint.

Advantages

LCN evidence has allowed convictions to be made in several

cold cases A cold case is a crime, or a suspected crime, that has not yet been fully resolved and is not the subject of a current criminal investigation, but for which new information could emerge from new witness testimony, re-examined archives, new or re ...

. 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

Aldershot Aldershot () is a town in Hampshire, England. It lies on heathland in the extreme northeast corner of the county, southwest of London. The area is administered by Rushmoor Borough Council. The town has a population of 37,131, while the Alders ...

. In 1999, a DNA profile was obtained from this using LCN. This was continually checked against the

UK National DNA Database The United Kingdom National DNA Database (NDNAD; officially the ''UK National Criminal Intelligence DNA Database'') is a national DNA Database that was set up in 1995. In 2005 it had 3.1 million profiles and in 2020 it had 6.6 million profiles ...

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. So far the technique is only used in several countries:the UK, the

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populous ...

and

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

Criticism

It has been used in more than 21,000 serious crime cases in the UK and internationally, particularly in "cold" cases. A FSS spokesman 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." However, the technique came under attack from the Judge during the trial of Sean Hoey – who was eventually cleared of involvement in the

Omagh Bombing The Omagh bombing was a car bombing on 15 August 1998 in the town of Omagh in County Tyrone, Northern Ireland. It was carried out by the Real Irish Republican Army (Real IRA), a Provisional Irish Republican Army (IRA) splinter group who oppose ...

. 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.Judgment in full: the Queen v Sean Hoey – Times Online
/ref> Following the Judge's ruling, the use of the technique was suspended in the UK, pending a review by the

. This review was completed and the suspension lifted on the January 14, 2008 with the CPS stating that it had not seen anything to suggest that any current problems exist with LCN''".

Notes

{{Reflist

References

Science Behind the Technique
FSS
Case closed
''

The Guardian ''The Guardian'' is a British daily newspaper. It was founded in 1821 as ''The Manchester Guardian'', and changed its name in 1959. Along with its sister papers ''The Observer'' and ''The Guardian Weekly'', ''The Guardian'' is part of the Gu ...

'', January 16, 2008
Statement of Dan E. Krane in the case of R. v. Sean Hoey
October 24, 2006 DNA profiling techniques Genetics in the United Kingdom Laboratory techniques

Advantages

Criticism

See also

Notes

References