Criminal Law Bulletin, 2010
46 Pages Posted: 25 Feb 2010
Date Written: February 2010
DNA typing has become the new "Gold Standard" in forensic science. In its February 2009 report, the National Academy of Science declared that "nuclear DNA analysis" is the only "forensic science method... rigorously shown to have the capacity to consistently, and with a high degree of certainty, demonstrate a connection between evidence and a specific individual or source." While the vast majority of the published opinions involve human DNA, litigants are now offering testimony about non-human DNA analysis with growing frequency. Evidence of canine DNA analysis has been admitted at trials in California, Florida, Illinois, Iowa, Oklahoma, Pennsylvania, and Washington.
Canine DNA analysts use essentially the same scientific techniques and terminology as human DNA analysts. Given the courts' receptivity to human DNA evidence, there is an understandable temptation to treat canine DNA evidence in roughly the same fashion as human DNA testimony. However, on closer scrutiny, there are important differences between the two types of DNA evidence. In particular, there are questions about the stability and reliability of the population frequency data used in the statistical evaluation of the significance of a match in canine DNA analysis.
This article compares and contrasts the use of nuclear DNA (nDNA) and mitochondrial DNA (mtDNA) analysis of canine and human DNA. The article identifies the salient differences between canine and human DNA analysis, notably with respect to the related statistics. In addition, the article critically evaluates some of the leading published opinions on canine DNA. Those opinions indicate that the bench and bar do not yet fully appreciate the differences between human and canine DNA analysis. On the one hand, compared to microscopic analysis of canine hair, the use of canine DNA analysis represents a distinct improvement. On the other hand, rather than facilely equating canine and human DNA analysis, the legal community must develop a more sophisticated understanding of the available empirical data on canine DNA.
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