By D.H. Kaye[*]
In a recent essay, Professor Simon Cole asks “Is the ‘Junk DNA’ designation bunk?” He concludes that in one sense, it is not. There is no scientific evidence that the specific DNA variations used to identify the sources of crime-scene DNA perform any biological functions. Nonetheless, he contends that this fact, in and of itself, does not obviate the concern that the specific STR profiles stored in law enforcement databases of offenders (and sometimes arrestees) might be used to extract medically or socially sensitive information. I agree and have said as much in the past.
Professor Cole also writes that “[t]he privacy threat posed by forensic STRs may not be great,” but he does not explain the basis for this view, and many of his remarks could be construed as being more consistent with the opposite conclusion—that the privacy threat may well be great. He criticizes the assurances of forensic scientists and human geneticists that, at present, “forensic DNA has no predictive value or medical significance” as “misleading” and “not fully informative.” He proposes that the records of the STR types of offenders contained in existing law enforcement databases “may, in fact, be precisely the kind of ‘predictive medical information’ that concerns privacy advocates,” and he refers to STRs as potential “markers” having “predictive utility.” In particular, he asserts that “the forensic STRs . . . correlate with . . . disease-causing genes” and “phenotypically perceived race.” He concludes that “[i]f some forensic STRs are correlated with genes that cause physical traits, . . . the public can [and should] be informed of that fact” so that it “can decide for itself whether and to what extent the privacy risk offsets the benefits of genetic databases.” The genetically influenced physical traits that he proposes are discernible from the DNA sequences used in criminal identification databases in the United States include diseases that would be of interest to insurance companies or employers and physical features associated with conventional racial categories.
These remarks require clarification. Just as the argument that nonfunctional DNA cannot be a threat to privacy is superficial, it would be incomplete and misleading simply to inform the public that an STR profile contains information that is correlated to physical traits such as disease and possibly behavioral predispositions and hence could be used to predict whether an individual will develop a disease. By innuendo, this formulation suggests that these nonfunctional loci, which are very weakly associated (if at all) with disease or behavior, are comparable to the loci used in much more powerful modern genetic testing for the DNA sequences of mutations that do cause disease.
This Colloquy Essay therefore analyzes in greater depth the medical and biological implications of the DNA records in the National DNA Index System (NDIS) and its local and state components. It explains why the STR profiles are useless as a “genetic test to screen for any particular disease.” No one can say for certain what the future of genetics holds, but based on current knowledge and practice, the information coded in the databases is and will remain, with the limited exceptions noted below, useful only for identification.
To develop these points, Part I briefly describes the four possible ways in which genetic loci could possess predictive or diagnostic value with regard to diseases and explains why these mechanisms have not led, and probably cannot lead, to useful screening tests with the Convicted Offender DNA Index System (CODIS) profiles in national, state, and local databases. Part II considers the “physical traits” and familial relationships that the CODIS STRs can be used to identify. That the profiles carry limited information about an individual’s race and familial relationships has long been part of the public dialogue, and Part II places the resulting privacy issues in perspective. Part III comments on analogies between STR types and fingerprints, social-security numbers, and the like, employed when discussing these issues in the public forum.