Friday, 8 August 2008

Sir Alec Jeffreys and DNA fingerprinting

The Independent

Inventor of DNA fingerprint testing warns flaw could lead to miscarriages of justice

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.

BBC

The inventor of DNA fingerprinting has offered to act as an expert witness in the Madeleine McCann case

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.

6 comments:

guerra said...

Unfortunately, many experts will testify either for the defence or prosecution based on how much money they are paid. It is my understanding that any reputable lab must indicate a probability that there could be a chance DNA match as they say. Was such a probability figure given by the FSS lab?

Anonymous said...

Boa noite, Paulo

And if inconclusive it would mean just that: inconclusive and "it is then up to investigators, the courts and all the rest of it" to search for evidence not so inconclusive.
But we're waiting for september to learn more about the 15, 10, 19 markers and the inconclusive results... and about the hair...
Till then, inconclusive.

Anonymous said...

ahh... e em setembro espero ouvir o Prof.Pinto da Costa

Anonymous said...

guerra,

Yes, 15 of 19 of Madeleine's DNA markers were found in the apartment and vehicle specimens.

Whilst any margine below 100% is termed 'inconclusive', the 88% match confirms the DNA belongs to no other.
15 out of 19 marker match is used in Court cases determining parentage claims.

FSS Birmingham is reportedly one of the bet laboratories in the world. Reports of McCanns paying others to run tests confirms the 'missing' quantity of hair specimens do, in fact, still exist and were not returned to PJ for good reason. Mr Amaral states in his book PJ requested them for analysis in Portugal.

DNA results confirm Madeleine died in the apartment, corpse specimens were also found in the boot vehicle. FSS also confirmed results showed DNA of 'two other peoples' ' DNA components (22 in total)alongside Madeleines. Cadaver specimens pinpointed by Eddie & Keela include the ID of 'two people' directly associated.

FSS/police were legally obliged check the 22 components against suspects DNA and pass the findings to the PJ. It's implausible that FSS did not comply to duty/legal requirements and/or withhold cadaver hair results. PJ's request for return of specimens was ignored. Likewise 'cuddle' cat was withheld to prevent standard forensic analysis.

Anonymous said...

guerra,

Yes, 15 of 19 of Madeleine's DNA markers were found in the apartment and vehicle specimens.

Whilst any margine below 100% is termed 'inconclusive', the 88% match confirms the DNA belongs to no other.
15 out of 19 marker match is used in Court cases determining parentage claims.

FSS Birmingham is reportedly one of the bet laboratories in the world. Reports of McCanns paying others to run tests confirms the 'missing' quantity of hair specimens do, in fact, still exist and were not returned to PJ for good reason. Mr Amaral states in his book PJ requested them for analysis in Portugal.

DNA results confirm Madeleine died in the apartment, corpse specimens were also found in the boot vehicle. FSS also confirmed results showed DNA of 'two other peoples' ' DNA components (22 in total)alongside Madeleines. Cadaver specimens pinpointed by Eddie & Keela include the ID of 'two people' directly associated.

FSS/police were legally obliged check the 22 components against suspects DNA and pass the findings to the PJ. It's implausible that FSS did not comply to duty/legal requirements and/or withhold cadaver hair results. PJ's request for return of specimens was ignored. Likewise 'cuddle' cat was withheld to prevent standard forensic analysis.

guerra said...

I know that 15 out of 19 markers matched the child's DNA. The probability figure I'm referring to, is the figure that is calculated based on the probability of each marker existing in the population. From the probability of the existence of each marker you can determine the probability of the DNA profile occurring by chance. I believe any reputable lab must attach this probability figure to their findings.