Surveillance: Citizens and the State - Constitution Committee Contents

Examination of Witnesses (Questions 154-159)

Professor Peter Hutton, Professor Graeme Laurie and Dr Helen Wallace

30 JANUARY 2008

  Q154  Chairman: Could I welcome you, Professor Hutton, Professor Laurie and Dr Wallace. It is extremely good of you to come and give evidence. We are not being televised but we are being recorded, so I would ask you, if I may, to state your names and organisations for the record, and thereafter to make a short opening statement if you so wish.

  Professor Hutton: My name is Professor Peter Hutton; I am here as the Chairman of the National DNA Ethics Group, which was set up as a non-departmental public body on 25 July last year. My full time employment is as a Professor of Anaesthesia and Honorary Consultant at the University Hospital, Birmingham, and Birmingham Medical School.

  Professor Laurie: Good morning; I am Professor Graeme Laurie from the University of Edinburgh Law School. I am also here as a representative of the Nuffield Council on Bioethics. I was recently a member of the Working Group on ethical issues related to bioinformation, and the terms of reference of that Council are to identify and define ethical questions raised in respect of biomedicine and bioethics and to report publicly on those issues.

  Dr Wallace: My name is Dr Helen Wallace. I am the Director of GeneWatch UK, which is a small, not for profit organisation set up about ten years ago. Our aim is to ensure that genetics is used in the public interest and to stimulate public debate about the applications of genetic technology.

  Q155  Chairman: Would anybody like to make a brief opening statement or shall we go straight to questioning?

  Professor Hutton: I am happy to go to the questions.

  Q156  Chairman: Could I ask, to begin with, if you could give us a brief explanation of the nature of DNA samples and profiles and how they are collected? And to what extent is the technology advancing?

  Professor Hutton: The DNA which is present in almost every cell of our body is identical on every occasion, although its activity differs from cell to cell. Of the DNA which is present in the cell only five per cent of that DNA is actually used to make body cells and components; the remaining 95 per cent of the DNA is what is termed scientifically as redundant DNA, that is, it has no known purpose in producing the cells of the body. It has other purposes about which people speculate, such as providing structural integrity to the molecule. When a forensic DNA test is done it is the redundant part of the DNA which is tested, not the section which is responsible for the production of cells. When we are conceived, we inherit 50 per cent of our DNA from our mother and 50 per cent from our father. The gene which, for instance, produces a normal compound such as insulin is probably the same in each parent. However, the redundant components of DNA differ greatly from person to person and that it is why it is that section which is used to differentiate identity. The tests which are done are done by applying substances called primers which stick to particular components of the DNA. Depending upon where they stick and the amount that they stick to determines your DNA profile, and that emerges either on a paper printout or on an electronic screen as a series of numbers and peaks, and for any one individual 50 per cent of those numbers and peaks will be determined by their mother and 50 per cent by their father. That is also true of a sibling but it is a different 50 per cent from each parent. In that way siblings are similar but inherently different to each other. The tests which are used in Britain are based on a system called SGM Plus, which stands for Second Generation Multiplex—that is the name of the machine—and Plus because it is a more advanced test. This tests the redundant DNA at ten positions and also identifies the sex chromosomes, and, in comparing DNA if you test the ten positions together with the sex chromosome the chance of a match at random is one in a billion. I think perhaps, my Lord, if I stop there people could ask questions.

  Q157  Chairman: Thank you very much indeed. Could I ask what estimate you would make about the reliability of DNA samples and profiles in the context of law enforcement?

  Dr Wallace: Perhaps I could answer that? I think it is clearly highly reliable; if you have a complete DNA profile from the individual and a complete DNA profile from the crime scene the match probability is roughly one in a billion.

  Q158  Chairman: Could you say that again?

  Dr Wallace: The probability of a match with an unrelated individual, if you have two full profiles, is around about one in a billion. However, there are quite a number of steps along the process where problems can arise. First, you will notice that I said an unrelated individual—there is of course a potential that relatives become the subject of an investigation and may be wrongly implicated. Secondly, there is a big issue about crime scene DNA but the crime scene itself is obviously a messy place to collect DNA samples and many of those samples do not give a complete DNA profile. So, for example, in 2005/2006 something like 50,000 of the match reports sent to the police involved a list of potential suspects and that was largely due to the fact that the crime scene DNA profiles were not complete. So it is a misunderstanding to think that a single individual is often implicated in the crime. The second point to emphasise also is that at a crime scene many people may have been present who are not necessarily the perpetrators, so you may also have a match with someone who has been at the crime scene earlier in the day, for example.

  Professor Laurie: May I just add that one of the significant technological developments that struck the Working Group was the ability to obtain DNA from smaller and smaller samples, known colloquially as low copy number, and this has been heavily criticised in the recent Omagh bombing trial and is currently being investigated by Sir Brian Caddy at the request of the interim Forensic Regulator. One of the concerns is the lack of scientific and international agreement about the reliability of this in terms of what it can actually say for matches in criminal trials and we understand that it has been reported that only three countries routinely rely on this sort of evidence—the United Kingdom, the Netherlands and New Zealand. Such a review was welcomed by the group because one of the main concerns of the Working Group was public trust and confidence in the quality of the forensic service provision.

  Q159  Baroness Quin: In the account of the ethical issues of the organisation in which you are involved it does say in paragraph three that in particular there are dangers of deliberate or accidental contamination, misinterpretation of mixed samples and mistaken interpretation of the partial profile. Are there examples that you know of where this has happened and where injustice has resulted?

  Professor Laurie: It is important to understand the context in which the report was actually drafted. It was not really the business of the Council to try and look for case studies; it was more to reassess the fundamental ethical principles upon which our entire system is actually based. A lot has to go wrong before there are actual specific incidences of miscarriages of justice but what comes out of our report is that the ethical principles we feel should inform the entire process are those of liberty, privacy and autonomy and there can be many intrusions on an individual's privacy before they actually get to court and before that may lead to problems of miscarriage, and it was really about getting the balance right between what is in the interests of society and the prosecution and detection of crime and citizens' interests of privacy and liberty.

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