UK DNA Mismatch

UK DNA Mismatch

Police Minister George Hawkins wants police powers broadened to take DNA samples, but Britain's DNA database computer has mistakenly mismatched an innocent man to a burglary. John Howard reports.

The DNA mismatch, thought to be the first major mistake produced by a national computer database, has sent shockwaves through law enforcement communities not only in Great Britain but also in the United States where DNA databases are based on the British model.

The mistaken identification was disclosed by British authorities last month during a meeting with members of the National Commission on the Future of DNA evidence.

Last year, the Manchester police lifted DNA from evidence left at the scene of a burglary.

The DNA was placed in the national database where a computer matched it to one of 666,000 previously arrested persons whose DNA was on file.

The DNA matched at six points of identification, or loci, along the DNA molecule.

British authorities estimated that the likelihood of that match occuring at random was one in 37 million.

But after the suspect provided an alibi, police asked for a retest.

This time a technique which examines 10 loci and has a one-in-one billion likelihood of mismatch was used.

British authorities say the mismatch was probably caused by the rapidly increasing size of the their database. As more profiles are added the possibility of suspects with very similar DNA increases.

"Everybody who has ever been convicted on six-point DNA profiling will want to apply to have their convictions reviewed," said Angela Flower, of the British Apeals Board.

An FBI spokesman in the US has called the mismatch "mind-blowing" because the US uses the British model of DNA testing.

The computer mismatch has recently been confirmed by the British Forensic Science Service and authorities now fear that the error could prompt thousands of people convicted on six-point DNA testing to appeal their convictions.

At the time of writing it has not be confirmed how many points of identification (loci) of the DNA molecule New Zealand uses to match samples.

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