In the DNA database debate that occurred during the election, one important point was quite often missed: namely that DNA evidence is not the infallible witness that is so often claimed.
We have written before about the dangers present in investing too much faith in DNA, but today the details of a study by the New Scientist have been revealed which further emphasise the flaws in the argument of those - like Philip Davies - that believe in putting everyone in the country on the DNA database.
The magazine sent a sample of DNA from a real crime scene to 17 experienced analysts in an U.S. laboratory. The experts' differing results cast doubts over the technique's reliability.
The sample, from a gang rape, had already been used to convict a man - but only one of the 17 scientists came to the same conclusion. Four said the evidence was inconclusive and 12 said he could be excluded.
Itiel Dror, a University College London scientist who helped set up the investigation, said: 'It is time DNA analysts accept that under certain conditions, subjectivity may affect their work.'
Christine Funk, a defence lawyer in the U.S., said: 'The difference between prison and freedom rests in the hands of the scientist assigned the case.'
That final line should put a shiver through anyone who believes in trial by jury. Hopefully studies like this can put an end to the sort of nonsense we saw from Alan Johnson and Harriet Harman when the pros and cons of removing innocent profiles from the database were being debated.
By Dylan Sharpe
"Exact sciences" often turn out to be rather disappointingly vague once you look beneath the facade.
Statistics, on which DNA analysis is based, are famous as a tool for misleading opinion.
The probabilities of winning the lottery are laughably small, yet it happens. It could be you.
See what I did there?
Posted by: Redacted | 13/08/2010 at 07:54 PM