News

The UK government has withdrawn its controversial proposals for the national DNA database (see BBC news report), which included keeping the DNA profiles of people without convictions for between six and twelve years (see previous news).

 

The proposals were open for public consultation from May to August 2009, during which time they received widespread condemnation from civil liberties campaigners citing Article 8 of the European Convention on Human Rights (which relates to personal privacy). In addition, the Government received criticism from wider scientific organisations and numerous individuals for the use of flawed and inappropriate statistical data as evidence to support the proposed measures (for example, see Bad Science article).

 

Following the consultation and resultant withdrawal of the Government’s proposals, a Home Office spokesman said they hoped to bring forward "further provisions" on DNA retention in the next policing and crime bill (see Guardian news article). It remains to be seen how police will respond in practice to any future legislation (or lack thereof), as current advice from the Association of Chief Police Officers is still to continue adding the DNA profiles of innocent individuals to the database (see Times news article).

 

Comment: It has been suggested that simply expanding the national DNA database to include DNA profiles from everyone in the UK – rather than only those accused of a crime – would be a fairer system and improve the ability of police to solve crimes. However, in addition to compelling civil rights arguments against such a system, as well as concerns over its broader social implications, there are also excellent technical reasons why enlarging the current DNA database may be unwise.

 

Firstly, new research has shown that DNA evidence can be faked using standard molecular biology techniques [Frumkin D et al. Forensic Sci Int Genet (2009) doi: 10.1016/j.fsigen.2009.06.009]. DNA profiles used for forensic purposes only contain a tiny amount of genetic sequence data, as they report simply on the number of repeated sequences at a handful of genetic loci in an individual (a ‘DNA fingerprint’). Therefore, artificial DNA can be synthesised to match any DNA fingerprint, either taken from a physical sample or an entry in a database. This synthetic DNA can subsequently be applied to surfaces and objects, or even incorporated into genuine human tissue (such as saliva or blood) from which cells from the donor individual are removed. This raises serious questions about security and the potential for misuse of DNA databases.

 

Secondly, there are strong statistical arguments against the application of such a large database in forensics. Not only does the complexity of storing and searching such a large body of data increase substantially with the size of the database, but so too does the probability of errors, duplicates and false entries. Moreover, the chance of getting a false positive match is also much higher, simply due to the vast number of comparisons involved and the percentage of the population who have similar (or identical) DNA fingerprints.

 

Finally, the National DNA Database Annual Report 2007-09, released by the National Policing Improvement Agency only days after the Government’s policy U-turn, indicates that the number of detections using DNA evidence has fallen by nearly 25% (10,000 crimes) over the last 2 years, despite the DNA database growing at almost the same rate (from 4.6 to 5.6 million profiles) over the same time period. This calls into question the assertion that more crimes will necessarily be solved if more individual profiles are on the DNA database. If this assumption – which underlies much of the support for the DNA database – is actually false, then arguments in favour of expansion are seriously undermined .