Validity of LCN
From the Ruling of Reed & Reed and Garmson:-
74. On the evidence before us, we consider we can express our opinion that it is clear that, on the present state of scientific development:
i) Low Template DNA can be used to obtain profiles capable of reliable interpretation if the quantity of DNA that can be analysed is above the stochastic threshold – that is to say where the profile is unlikely to suffer from stochastic effects (such as allelic drop out mentioned at paragraph 48) which prevent proper interpretation of the alleles.
ii) There is no agreement among scientists as to the precise line where the stochastic threshold should be drawn, but it is between 100 and 200 picograms.
iii) Above that range, the LCN process used by the FSS can produce electrophoretograms which are capable of reliable interpretation. There may, of course, be differences between the experts on the interpretation, for example as to whether the greater number of amplifications used in this process has in the particular circumstances produced artefacts and the effect of such artefacts on the interpretation. Care may also be needed in interpretation where the LCN process is used on larger quantities than that for which it is normally used. However a challenge to the validity of the method of analysing Low Template DNA by the LCN process should no longer be permitted at trials where the quantity of DNA analysed is above the stochastic threshold of 100-200 picograms in the absence of new scientific evidence. A challenge should only be permitted where new scientific evidence is properly put before the trial court at a Plea and Case Management Hearing (PCMH) or other pre-trial hearing for detailed consideration by the judge in the way described at paragraphs 129 and following below.
iv) As we have mentioned, it is now the practice of the FSS to quantify the amount of DNA before testing. There should be no difficulty therefore in ascertaining the quantity and thus whether it is above the range where it is accepted that stochastic effects should not prevent proper interpretation of a profile.
v) There may be cases where reliance is placed on a profile obtained where the quantity of DNA analysed is within the range of 100-200 picograms where there is disagreement on the stochastic threshold on the present state of the science. We would anticipate that such cases would be rare and that, in any event, the scientific disagreement will be resolved as the science of DNA profiling develops. If such a case arises, expert evidence must be given as to whether in the particular case, a reliable interpretation can be made. We would anticipate that such evidence would be given by persons who are expert in the science of DNA and supported by the latest research on the subject. We would not anticipate there being any attack on the good faith of those who sought to adduce such evidence.
75. In reaching this view we have taken account of the evidence of Dr Budowle. In his report, he set out his view that LCN was not a robust technology; for example samples not susceptible to SGM+ analysis contain too little DNA and yield inherently non-reproducible results. At one stage of his evidence he appeared to accept the conclusions we have set out; he then appeared to go back on this. It might therefore have appeared that he had contradicted himself. If that had been the case, it would have cast grave doubts about the value of his evidence. We think, however, from a detailed consideration of the transcript that he did not, in the result, resile from his acceptance of the conclusions we have set out, but was rightly seeking to draw attention to the need for careful interpretation and to the need for an expert to take considerable care in the conclusions expressed. We have also considered his comments about the protocols and guidelines for the interpretation of LCN DNA with which he had been provided, but the materials before us did not support the observations he made.
KR,
Vic.
From the Ruling of Reed & Reed and Garmson:-
74. On the evidence before us, we consider we can express our opinion that it is clear that, on the present state of scientific development:
i) Low Template DNA can be used to obtain profiles capable of reliable interpretation if the quantity of DNA that can be analysed is above the stochastic threshold – that is to say where the profile is unlikely to suffer from stochastic effects (such as allelic drop out mentioned at paragraph 48) which prevent proper interpretation of the alleles.
ii) There is no agreement among scientists as to the precise line where the stochastic threshold should be drawn, but it is between 100 and 200 picograms.
iii) Above that range, the LCN process used by the FSS can produce electrophoretograms which are capable of reliable interpretation. There may, of course, be differences between the experts on the interpretation, for example as to whether the greater number of amplifications used in this process has in the particular circumstances produced artefacts and the effect of such artefacts on the interpretation. Care may also be needed in interpretation where the LCN process is used on larger quantities than that for which it is normally used. However a challenge to the validity of the method of analysing Low Template DNA by the LCN process should no longer be permitted at trials where the quantity of DNA analysed is above the stochastic threshold of 100-200 picograms in the absence of new scientific evidence. A challenge should only be permitted where new scientific evidence is properly put before the trial court at a Plea and Case Management Hearing (PCMH) or other pre-trial hearing for detailed consideration by the judge in the way described at paragraphs 129 and following below.
iv) As we have mentioned, it is now the practice of the FSS to quantify the amount of DNA before testing. There should be no difficulty therefore in ascertaining the quantity and thus whether it is above the range where it is accepted that stochastic effects should not prevent proper interpretation of a profile.
v) There may be cases where reliance is placed on a profile obtained where the quantity of DNA analysed is within the range of 100-200 picograms where there is disagreement on the stochastic threshold on the present state of the science. We would anticipate that such cases would be rare and that, in any event, the scientific disagreement will be resolved as the science of DNA profiling develops. If such a case arises, expert evidence must be given as to whether in the particular case, a reliable interpretation can be made. We would anticipate that such evidence would be given by persons who are expert in the science of DNA and supported by the latest research on the subject. We would not anticipate there being any attack on the good faith of those who sought to adduce such evidence.
75. In reaching this view we have taken account of the evidence of Dr Budowle. In his report, he set out his view that LCN was not a robust technology; for example samples not susceptible to SGM+ analysis contain too little DNA and yield inherently non-reproducible results. At one stage of his evidence he appeared to accept the conclusions we have set out; he then appeared to go back on this. It might therefore have appeared that he had contradicted himself. If that had been the case, it would have cast grave doubts about the value of his evidence. We think, however, from a detailed consideration of the transcript that he did not, in the result, resile from his acceptance of the conclusions we have set out, but was rightly seeking to draw attention to the need for careful interpretation and to the need for an expert to take considerable care in the conclusions expressed. We have also considered his comments about the protocols and guidelines for the interpretation of LCN DNA with which he had been provided, but the materials before us did not support the observations he made.
KR,
Vic.
Comment