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Chapter 5 that will make the principle more workable and less susceptible to creative misapplications.

DNA in the Courts

Prior to 1992, there was controversy over our two main issues, laboratory error and population substructure. The 1992 NRC report was intended to resolve the controversy, but the arguments went on. One reason is that the scientific community has not spoken with one voice; defense and prosecution witnesses have given highly divergent statistical estimates or have disagreed as to the validity of all estimates. For this reason, some courts have held that the analyses are not admissible in court. The courts, however, have accepted the soundness of the typing procedures, especially for VNTRs. The major disagreement in the courts has been over population substructure and possible technical or human errors. The interim ceiling principle, in particular, has also been the subject of considerable disagreement. We hope that our report will ease the acceptance of DNA analysis in the courts and reduce the controversy.

We shall not summarize the various court findings and opinions here. The interested reader can find this information in Chapter 6, which also discusses the implications that our recommendations could have on the production and introduction of DNA evidence in court proceedings.

Conclusions and Recommendations

Conclusions and recommendations are given at the ends of the chapters in which the relevant subject is discussed. For convenience, they are repeated here.

Admissibility of DNA Evidence (Chapter 2)

DNA analysis is one of the greatest technical achievements for criminal investigation since the discovery of fingerprints. Methods of DNA profiling are firmly grounded in molecular technology. When profiling is done with appropriate care, the results are highly reproducible. In particular, the methods are almost certain to exclude an innocent suspect.

One of the most widely used techniques involves VNTRs. These loci are extremely variable, but individual alleles cannot be distinguished, because of intrinsic measurement variability, and the analysis requires statistical procedures. The laboratory procedure involves radioactivity and requires a month or more for full analysis. PCR-based methods are prompt, require only a small amount of material, and can yield unambiguous identification of individual alleles.

The state of the profiling technology and the methods for estimating frequencies and related statistics have progressed to the point where the admissibility of properly collected and analyzed DNA data should not be in doubt. We expect