Lincoln: Editorial - DNA Debate 185
Editorial -
DNA Debate
PATRICK J LINCOLN, SSe PhD FRCPath. Department of Haematology, London Hospital Medical College, Turner Street, London E1 2AD
The availability of DNA profiling in forensic science arguably has been the most dramatic advance that has ever occurred in the field but its acceptance, especially in the Courts, has not been without its own flurries of drama. In theory, the DNA, the basic genetic material which carries the code for all the inherited attributes of the body, will be unique to every person and although the forensic scientist will not investigate the total DNA in an individual it is possible from that which is investigated to obtain exceedingly high levels of individualization even if not uniqueness. The essence of the DNA profiling tests generally utilized by forensic scientists is that the thread-like DNA molecules are cut into fragments which are then sorted according to size and visualized in the form of bands, the position of which on an X-ray film reflects the size of the DNA fragment giving rise to the band. The large number of alternative sizes of the fragments that can occur at each particular location on the thread of DNA gives rise to a high power of discrimination between individuals; hence the usefulness of such testing. Three aspects of the DNA testing process can be identified: 1. Laboratory analysis of the DNA extracted from the test samples to demonstrate the presence of fragments (bands) produced from various sites on the DNA. 2. Comparison of the bands produced from different samples to see whether they match and thus whether the samples could have originated from the same source. 3. When the bands are considered to match, The statistical assessment of the frequency with which the bands are likely to be found in the population so that the chance of finding matching bands in samples from different persons can be calculated.
All three areas - the quality and reliability of the testing, the criteria for matching and the statistical evaluation of the results - have been areas for lively discussion and dispute. It is not surprising that the existence of technology with such enormous potential has meant that there has been intense pressure for its implementation as soon as possible and also that commercial interest, relatively unknown in this field previously in the UK, would become an important aspect. It has been suggested that never before have such complex laboratory procedures been transferred so rapidly to the Court room and that the introduction of the technology into forensic science in the USA was too hasty and without adequate regulations and safeguards (Easteal et al., 1991).
The forensic science community has worked hard not only to get to grips with the technology that was mostly new to them, but also to address concerns relating to the quality of the results produced. Great effort has been made by forensic scientists to ensure the continuing high standards which have become expected of them; for example, the International Society for Forensic Haemogenetics set up a DNA Commission which has published two reports (Brinkmann et al., 1989, 1992) concerning its recommendations for the use of DNA testing in the forensic field. In Europe, initiatives from the UK resulted in the setting up of a European DNA Profiling (EDNAP) group to look at ways of standardizing the technology so that results obtained from different laboratories could be compared; this group has published two papers (Schneider et al., 1991; Gill et al., 1992) giving the results of their collaborative exercises. In the USA the Technical Working Group on DNA Analysis Methods (TWGDAM) was set up.
186 Mad. Sci. Law (1992) Vol. 32, No.3
The main body of contest concerning the reliability and acceptance of DNA results in the Courts has occurred in the USA and a series of well-documented cases has received considerable publicity, even at the international level (for example Anderson, 1989; Norman, 1989; Lander, 1989). Whilst much of the Forensic Science in the USA emanates from the laboratories of the FBI a considerable volume of the work is performed in commercial laboratories in the private sector. The debate concerning the acceptability of DNA evidence in the Courts of the USA reached such a crescendo that in 1989 a study was initiated by the National Research Council of the National Academy of Sciences in America to look into 'DNA Technology in Forensic Science'. Its long awaited report was published on 16 April 1992 (see references). An article in the New York Times on 14 April 1992, presumably based on the prepublication copy of the report, carried a headline 'Judges are asked to Bar Genetic "Fingerprinting" Until Basis of Science is Stronger'. The article claimed that the report by the National Academy of Sciences said that 'Courts should cease to admit DNA evidence until laboratory standards have been tightened and the technique has been established on a stronger scientific basis'. Similar reports appear to have found their way into the British Press. The Chairman, of the National Academy of Sciences Committee, Dr Victor A. McKusick, called a news conference immediately to state that the New York Times report misrepresented the findings of the Committee. The following day the science editor of the New York Times stated they had erred in their article and headline in saying that the panel called directly for a moratorium on the use of DNA typing. However it seems clear from the New York Times report of 15 April that the matter is unlikely to end here. The article goes on to report the canvassed views of various lawyers and molecular biologists including some members of the National Academy of Sciences Committee, and it is obvious that there are considerable differences in opinion concerning the interpretation of the findings of the report, ranging from the view that DNA can continue to be used in the Courts without interruption to the other
extreme that the recommendations are tantamount to saying DNA evidence should not be admissible at this time. Two important areas of continued discussion include the recommendations relating to quality assurance and the fact that these are not yet being met and, secondly, the area of population genetics and the occurrence of subpopulations which could have influence on the statistical evaluation of results. It seems, certainly in the USA, all has not been resolved by the report from the National Academy of Sciences Committee and the discussion is likely to continue at least in the sense that the words of their document will be fought over in the Courts, albeit at great expense as far as defence and prosecution experts, lawyers and Court time is concerned.
REFERENCES Alun Anderson (1989) DNA fingerprinting on trial. Nature 342, 21/28 Dec. p. 844. Brinkmann B., Butler R., Lincoln P., Mayr W. and Rossi U. (1989) Recommendations of the Society for Forensic Haemogenetics concerning DNA polymorphisms. For. Sci. Int. 43, 109-11. Brinkmann B., Butler R., Lincoln P., Mayr W. and Rossi U. (1991) Report concerning recommendations of the DNA Commission of the International Society for Forensic Haemogenetics relating to the use of DNA polymorphisms. For. Sci. Int. 52 12530. DNA Technology in Forensic Science (1992) National Research Council. National Academy Press, Washington DC. ISBN 0-309-04587-8. Easteal S., McLeod N. and Reed K (1991) DNA Profiling. Principles, Pitfalls & Potential. Harwood Academic Publications. Gill, P., Woodroffe S., Bar w., Brinkmann B, Carracedo A, Eriksen B., Jones S., Kloosterman A D., Ludes B., Mevag B., Pascali V. L., Rudler M., Schmitter H., Schneider P. M. and Thomson, J. A (1992) Report of an International collaborative experiment to demonstrate the uniformity obtainable using DNA profiling techniques. For. Sci. Int. 53 29-43. Eric SLander (1989) DNA fingerprinting on trial. Nature 339, 15 June from p. 501 Colin Norman (1989) Maine case deals blow to DNA fingerprinting. Science 246 22 Dec. pp. 1556--8. Schneider P. M., Fimmers R., Woodroffe S., Werrett D. J., Bar W., Brinkmann B., Eriksen B., Jones S., Kloosterman A D., Mevag B., Pascali V. L., Rittner C., Schmitter H, Thomson J. A and Gill P. (1991) Report of a European collaborative exercise comparing DNA typing results using a single locus VNTR probe. For. &i. Int. 49 1-15.
Editorial -
DNA Debate
PATRICK J LINCOLN, SSe PhD FRCPath. Department of Haematology, London Hospital Medical College, Turner Street, London E1 2AD
The availability of DNA profiling in forensic science arguably has been the most dramatic advance that has ever occurred in the field but its acceptance, especially in the Courts, has not been without its own flurries of drama. In theory, the DNA, the basic genetic material which carries the code for all the inherited attributes of the body, will be unique to every person and although the forensic scientist will not investigate the total DNA in an individual it is possible from that which is investigated to obtain exceedingly high levels of individualization even if not uniqueness. The essence of the DNA profiling tests generally utilized by forensic scientists is that the thread-like DNA molecules are cut into fragments which are then sorted according to size and visualized in the form of bands, the position of which on an X-ray film reflects the size of the DNA fragment giving rise to the band. The large number of alternative sizes of the fragments that can occur at each particular location on the thread of DNA gives rise to a high power of discrimination between individuals; hence the usefulness of such testing. Three aspects of the DNA testing process can be identified: 1. Laboratory analysis of the DNA extracted from the test samples to demonstrate the presence of fragments (bands) produced from various sites on the DNA. 2. Comparison of the bands produced from different samples to see whether they match and thus whether the samples could have originated from the same source. 3. When the bands are considered to match, The statistical assessment of the frequency with which the bands are likely to be found in the population so that the chance of finding matching bands in samples from different persons can be calculated.
All three areas - the quality and reliability of the testing, the criteria for matching and the statistical evaluation of the results - have been areas for lively discussion and dispute. It is not surprising that the existence of technology with such enormous potential has meant that there has been intense pressure for its implementation as soon as possible and also that commercial interest, relatively unknown in this field previously in the UK, would become an important aspect. It has been suggested that never before have such complex laboratory procedures been transferred so rapidly to the Court room and that the introduction of the technology into forensic science in the USA was too hasty and without adequate regulations and safeguards (Easteal et al., 1991).
The forensic science community has worked hard not only to get to grips with the technology that was mostly new to them, but also to address concerns relating to the quality of the results produced. Great effort has been made by forensic scientists to ensure the continuing high standards which have become expected of them; for example, the International Society for Forensic Haemogenetics set up a DNA Commission which has published two reports (Brinkmann et al., 1989, 1992) concerning its recommendations for the use of DNA testing in the forensic field. In Europe, initiatives from the UK resulted in the setting up of a European DNA Profiling (EDNAP) group to look at ways of standardizing the technology so that results obtained from different laboratories could be compared; this group has published two papers (Schneider et al., 1991; Gill et al., 1992) giving the results of their collaborative exercises. In the USA the Technical Working Group on DNA Analysis Methods (TWGDAM) was set up.
186 Mad. Sci. Law (1992) Vol. 32, No.3
The main body of contest concerning the reliability and acceptance of DNA results in the Courts has occurred in the USA and a series of well-documented cases has received considerable publicity, even at the international level (for example Anderson, 1989; Norman, 1989; Lander, 1989). Whilst much of the Forensic Science in the USA emanates from the laboratories of the FBI a considerable volume of the work is performed in commercial laboratories in the private sector. The debate concerning the acceptability of DNA evidence in the Courts of the USA reached such a crescendo that in 1989 a study was initiated by the National Research Council of the National Academy of Sciences in America to look into 'DNA Technology in Forensic Science'. Its long awaited report was published on 16 April 1992 (see references). An article in the New York Times on 14 April 1992, presumably based on the prepublication copy of the report, carried a headline 'Judges are asked to Bar Genetic "Fingerprinting" Until Basis of Science is Stronger'. The article claimed that the report by the National Academy of Sciences said that 'Courts should cease to admit DNA evidence until laboratory standards have been tightened and the technique has been established on a stronger scientific basis'. Similar reports appear to have found their way into the British Press. The Chairman, of the National Academy of Sciences Committee, Dr Victor A. McKusick, called a news conference immediately to state that the New York Times report misrepresented the findings of the Committee. The following day the science editor of the New York Times stated they had erred in their article and headline in saying that the panel called directly for a moratorium on the use of DNA typing. However it seems clear from the New York Times report of 15 April that the matter is unlikely to end here. The article goes on to report the canvassed views of various lawyers and molecular biologists including some members of the National Academy of Sciences Committee, and it is obvious that there are considerable differences in opinion concerning the interpretation of the findings of the report, ranging from the view that DNA can continue to be used in the Courts without interruption to the other
extreme that the recommendations are tantamount to saying DNA evidence should not be admissible at this time. Two important areas of continued discussion include the recommendations relating to quality assurance and the fact that these are not yet being met and, secondly, the area of population genetics and the occurrence of subpopulations which could have influence on the statistical evaluation of results. It seems, certainly in the USA, all has not been resolved by the report from the National Academy of Sciences Committee and the discussion is likely to continue at least in the sense that the words of their document will be fought over in the Courts, albeit at great expense as far as defence and prosecution experts, lawyers and Court time is concerned.
REFERENCES Alun Anderson (1989) DNA fingerprinting on trial. Nature 342, 21/28 Dec. p. 844. Brinkmann B., Butler R., Lincoln P., Mayr W. and Rossi U. (1989) Recommendations of the Society for Forensic Haemogenetics concerning DNA polymorphisms. For. Sci. Int. 43, 109-11. Brinkmann B., Butler R., Lincoln P., Mayr W. and Rossi U. (1991) Report concerning recommendations of the DNA Commission of the International Society for Forensic Haemogenetics relating to the use of DNA polymorphisms. For. Sci. Int. 52 12530. DNA Technology in Forensic Science (1992) National Research Council. National Academy Press, Washington DC. ISBN 0-309-04587-8. Easteal S., McLeod N. and Reed K (1991) DNA Profiling. Principles, Pitfalls & Potential. Harwood Academic Publications. Gill, P., Woodroffe S., Bar w., Brinkmann B, Carracedo A, Eriksen B., Jones S., Kloosterman A D., Ludes B., Mevag B., Pascali V. L., Rudler M., Schmitter H., Schneider P. M. and Thomson, J. A (1992) Report of an International collaborative experiment to demonstrate the uniformity obtainable using DNA profiling techniques. For. Sci. Int. 53 29-43. Eric SLander (1989) DNA fingerprinting on trial. Nature 339, 15 June from p. 501 Colin Norman (1989) Maine case deals blow to DNA fingerprinting. Science 246 22 Dec. pp. 1556--8. Schneider P. M., Fimmers R., Woodroffe S., Werrett D. J., Bar W., Brinkmann B., Eriksen B., Jones S., Kloosterman A D., Mevag B., Pascali V. L., Rittner C., Schmitter H, Thomson J. A and Gill P. (1991) Report of a European collaborative exercise comparing DNA typing results using a single locus VNTR probe. For. &i. Int. 49 1-15.
