The scientist who invented DNA fingerprinting two decades ago warned yesterday that the huge expansion of the national database - which now contains details of 2.5 million criminals - could contain mistakes and lead to miscarriages of justice. (...) Professor Sir Alec Jeffreys said forensic specialists might not be using a sufficiently accurate DNA match when comparing suspects with forensic material retrieved from a crime scene. Only 10 different DNA markers were used on the database to distinguish between individuals, he said.
"If you have a database of 2.5 million people you will start having matches. The current DNA database uses 10 distinct markers and I think there is still a residual risk of a false match. They should use about 15 markers because otherwise it leaves open the possibility that the match from the crime scene sample is genuine but a fluke (...) Sir Alec was working in a laboratory at the University of Leicester on 10 September 1984 when he stumbled across the key to the future of genetic research and development. (...) The Home Office says the database is being used on average to link suspects to 15 murders, 31 rapes and 770 car crimes every month.
Sir Alec Jeffreys said DNA matches alone did not establish guilt and all Madeleine's genetic characters would be found in at least one family member. Gerry and Kate McCann, suspects in their daughter's disappearance, are considering commissioning independent tests on a Portuguese hire car (...) In an exclusive interview with the BBC's Newsnight programme, Sir Alec said there could be a potential problem in assigning a profile to Madeleine given that all other members of her family would have been in the car. "DNA testing seeks to establish whether DNA sample A from a crime scene, came or did not come from individual B," he said. "So if you get a match there's very strong evidence that it did come from B.
“It is then up to investigators, the courts and all the rest of it to work out whether that connection is relevant or not. DNA doesn't have the words innocence or guilt in it - that is a legal concept. What it seeks to establish is connections and identifications (...)"
Thank you, S.