In a world where Western countries are running from the tide of DNA data that is washing over them, the United Arab Emirates seems to be taking a totally different stance.  At the moment, the UAE only collects samples from suspects or convicted criminals.  What they are looking at doing is expanding the DNA database to include every citizen (and I use the term in a colloquial sense, not a Border Control sense) – so that’s the entire population, both local and expatriate.  The thinking behind this is to assist with victim identification following mass disasters (natural and, presumably, man-made) and also to assist in missing persons cases.  They also apparently consider that it will drastically control crime,  reduce the number of unnecessary suspects and innocent suspects and reveal the real criminal in a case faster than at present.

The samples will start being collected within the next year, starting with the youngest end of the population, taking 1 million samples per year (that’s more than 2,700 each day).  Rather than write new legislation, the population could just be issued with a Security Directive to give a sample.

In a country with a population around the 4 and a half million mark and expanding rapidly, that’s a lot of DNA data, given that they currently have only 5,000 profiles on the current database .  I just hope their statistical interpretation software is up to the job.

Who has ever analysed the data in national DNA databases?  Courtesy of programs like CSI and the news/media, we all know that DNA can be an extremely powerful tool in crime solution.  When a sample from a crime scene is compared with a sample from an individual it should be the easiest thing to be able to say whether or not they originated from one and the same person, shouldn’t it?

In forensic science (and many other areas of science), without a solid and reliable database, interpretation of results can be troublesome or even meaningless.  So who has checked all the databases that have been built up by Police and prosecution agencies over the years?  Who checks them to make sure that the data is correctly entered or that the statistical basis for the interpretation is still correct and appropriate?  As it turns out, it doesn’t appear that anyone is really doing it, particularly in relation to the USA.  An article in this week’s New Scientist demonstrates this: Unreliable evidence? Time to open up DNA databases. Most of the world’s DNA results (and I am talking about those relating to criminal casework) are interpreted using the results of relatively small studies undertaken during the early years of DNA forensic casework.

The opening two paragraphs of the article cover it quite nicely, I think: “When a defendant’s DNA appears to match DNA found at a crime scene, the probability that this is an unfortunate coincidence can be central to whether the suspect is found guilty. The assumptions used to calculate the likelihood of such a fluke – the “random match probability” – are now being questioned by a group of 41 scientists and lawyers based in the US and the UK. These assumptions have never been independently verified on a large sample of DNA profiles, says the group. What’s more, whether some RMPs are truly as vanishingly small as assumed has been called into question by recent insights into DNA databases in the US and Australia. I find that slightly unnerving because I know from professional experience that if a DNA result is presented in court, it’s unbelievably difficult to shake anyone’s faith in the result.

I’m not suggesting that there is anything significantly wrong with any of the DNA databases but they should be open to examination by independent scientists so that the reliance that is placed on DNA interpretations can be shown to be well-placed. It makes the results relevant and reliable, which is important for acceptance as evidence in court.

The article does a good job of explaining the problems associated with DNA databases, describing three possible reasons why some profiles on the reference databases match one another (if they are all from different people then they should all be different): 1. duplication of the same profile in the database; 2. assumptions about frequency of occurrence of allelles in populations (see article for definition); and 3. the large number of relatives that may be on a given database (people who are closely related share more common areas of DNA in their profiles than people who are unrelated, which is logical). Particularly in relation to the latter point, if only a partial profile is obtained from a crime scene (i.e. only part of the DNA profile ‘picture’ can be detected), the chances increase of the sample matching more than one person’s database profile. (N.B.  There are essentially two sets of information in DNA databases – DNA profiles obtained from crime scene samples (so initially we don’t know who is the source of them) and DNA profiles taken from actual known people, usually suspects (depending on the legal jurisdiction)).

Of course, the converse of this is that if a DNA profile in the database has been incorrectly entered in some way, the chances of getting a “hit” on a cold case are also affected (a “hit on a cold case” is where re-examination of evidence is undertaken some time after a crime was committed, usually years afterwards, and a newly-acquired crime scene DNA result is run through the database for the first time.  If the crime scene profile matches a person’s profile already on the database, you’ve got a “hit”).  If the data’s not correct in the database, a ‘hit’ might become a ‘miss’.

The big question is whether the FBI will allow a group of independent scientists to review the USA’s CODIS database – and the answer at the moment is no.  This to me is a fairly typical attitude of prosecution agencies for this kind of access.  I can understand their reluctance in a way but I would think it would be a better thing to have it reviewed now rather than wait for a case to demonstrate a monumental stuff-up and get beaten with the consequences later, particularly to have it reviewed by people who would sign confidentiality agreements and then look at the data as a whole rather than focussing on one case where there may well be a problem.  As the closing commentary says, “Without external scrutiny of the databases, doubts will remain….All of this can be resolved by letting scientists have access to the data to do what they need to do.“  We all have our dreams, and I hope theirs comes true.

[The New Scientist article is based on a Science article, December 2009, v.236, p.5960]

Who has ever analysed the data in national DNA databases?  Courtesy of programs like CSI and the news/media, we all know that DNA can be an extremely powerful tool in crime solution.  When a sample from a crime scene is compared with a sample from an individual it should be the easiest thing to be able to say whether or not they originated from one and the same person, shouldn’t it?

In forensic science (and many other areas of science), without a solid and reliable database, interpretation of results can be troublesome or even meaningless.  So who has checked all the databases that have been built up by Police and prosecution agencies over the years?  Who checks them to make sure that the data is correctly entered or that the statistical basis for the interpretation is still correct and appropriate?  As it turns out, it doesn’t appear that anyone is really doing it, particularly in relation to the USA.  An article in this week’s New Scientist demonstrates this: Unreliable evidence? Time to open up DNA databases. Most of the world’s DNA results (and I am talking about those relating to criminal casework) are interpreted using the results of relatively small studies undertaken during the early years of DNA forensic casework.

The opening two paragraphs of the article cover it quite nicely, I think: “When a defendant’s DNA appears to match DNA found at a crime scene, the probability that this is an unfortunate coincidence can be central to whether the suspect is found guilty. The assumptions used to calculate the likelihood of such a fluke – the “random match probability” – are now being questioned by a group of 41 scientists and lawyers based in the US and the UK. These assumptions have never been independently verified on a large sample of DNA profiles, says the group. What’s more, whether some RMPs are truly as vanishingly small as assumed has been called into question by recent insights into DNA databases in the US and Australia. I find that slightly unnerving because I know from professional experience that if a DNA result is presented in court, it’s unbelievably difficult to shake anyone’s faith in the result.

I’m not suggesting that there is anything significantly wrong with any of the DNA databases but they should be open to examination by independent scientists so that the reliance that is placed on DNA interpretations can be shown to be well-placed. It makes the results relevant and reliable, which is important for acceptance as evidence in court.

The article does a good job of explaining the problems associated with DNA databases, describing three possible reasons why some profiles on the reference databases match one another (if they are all from different people then they should all be different): 1. duplication of the same profile in the database; 2. assumptions about frequency of occurrence of allelles in populations (see article for definition); and 3. the large number of relatives that may be on a given database (people who are closely related share more common areas of DNA in their profiles than people who are unrelated, which is logical). Particularly in relation to the latter point, if only a partial profile is obtained from a crime scene (i.e. only part of the DNA profile ‘picture’ can be detected), the chances increase of the sample matching more than one person’s database profile. (N.B.  There are essentially two sets of information in DNA databases – DNA profiles obtained from crime scene samples (so initially we don’t know who is the source of them) and DNA profiles taken from actual known people, usually suspects (depending on the legal jurisdiction)).

Of course, the converse of this is that if a DNA profile in the database has been incorrectly entered in some way, the chances of getting a “hit” on a cold case are also affected (a “hit on a cold case” is where re-examination of evidence is undertaken some time after a crime was committed, usually years afterwards, and a newly-acquired crime scene DNA result is run through the database for the first time.  If the crime scene profile matches a person’s profile already on the database, you’ve got a “hit”).  If the data’s not correct in the database, a ‘hit’ might become a ‘miss’.

The big question is whether the FBI will allow a group of independent scientists to review the USA’s CODIS database – and the answer at the moment is no.  This to me is a fairly typical attitude of prosecution agencies for this kind of access.  I can understand their reluctance in a way but I would think it would be a better thing to have it reviewed now rather than wait for a case to demonstrate a monumental stuff-up and get beaten with the consequences later, particularly to have it reviewed by people who would sign confidentiality agreements and then look at the data as a whole rather than focussing on one case where there may well be a problem.  As the closing commentary says, “Without external scrutiny of the databases, doubts will remain….All of this can be resolved by letting scientists have access to the data to do what they need to do.“  We all have our dreams, and I hope theirs comes true.

[The New Scientist article is based on a Science article, December 2009, v.236, p.5960]

A full crime scene DNA profile of the 22-year-old Teresa’s murder in a pub car park was developed as part of a case review.  Experts at the Forensic Science Service were able to test samples taken from killer David Lace’s body after it was dramatically exhumed from Kingston Cemetery in New Road, Copnor, last month.  The News understands the rigorous scientific tests involved the grim process of taking samples of bone or teeth from Lace’s remains, sanding or airblasting them to remove any contamination and then painstakingly extracting the DNA to enable a profile to be created.  Lace’s profile was checked against samples taken from the original crime scene at the rear of the Tom Tackle pub in Commercial Road, Southampton.  Results showed there is a one-in-a-billion chance of Lace not being responsible for her death.  The profile also matched that of Lace’s sister held on the National DNA Database.

Detective Chief Inspector Phil McTavish, who lead the fresh investigation, said: ‘At the time (of the murder], all detectives had to go on was blood groups.  ‘Now we had the DNA profile, we could start the elimination process in line with the background research of the case papers we were reviewing at the same time.  ‘The Forensic Science Service looked across the DNA database to find a match. The database threw up 30,000 results.  A lot of people on the DNA database don’t have criminal records. It was a process where we used some focussed research to focus on the most likely matches.  We found a match with a sibling, a sister of his.   Combined with the evidence gathered on the case papers, we sought approval from the Ministry of Justice to exhume David Lace’s grave.’

Hampshire Constabulary is ‘fully satisfied’ that the person exhumed from Kingston Cemetery was David Lace and that his DNA profile is a complete match for that of the suspect.   DCI McTavish said: ‘A match probability of one-in-one-billion has been given which basically means that the chances of obtaining a similar match from a person selected at random is of the order of one-in-one-billion.   He added: ‘The DNA result together with a full file of evidence has been submitted to Mr Alistair Nisbet of the Crown Prosecution Service for review and it has been determined that, had David Lace been alive today then there is a realistic prospect that a jury would properly conclude that he raped and murdered Teresa de Simone on December 5, 1979.  ‘Accordingly, if he was alive, Mr Nisbet would authorise that David Lace would be charged and prosecution commenced.  As a consequence of this decision and, taken together with the outcome of the extensive investigations we have undertaken, we are satisfied that we have identified the man responsible for the murder and rape of Teresa de Simone and we are not seeking any other person in relation to this case.  Additionally, we are not currently linking David Lace to any other undetected serious crime.”

EXHUMED Police at Kingston Cemetery where David Lace was buried