Thursday, January 3, 2013

"Scientists' Brief" on CODIS Loci: Q & A

On November 9, 2012, the Supreme Court voted to review a case posing the following question: “Does the Fourth Amendment allow the States to collect and analyze DNA from people arrested and charged with serious crimes?” In Maryland v. King, the state’s supreme court concluded that the protection against unreasonable searches and seizures forbids the state from collecting DNA from an individual whose true identity can be established with ordinary fingerprints. On December 28, 2012, the Supreme Court received a Brief of Genetics, Genomics and Forensic Science Researchers as Amici Curiae. Below are several questions and answers about the brief.

Who contributed to the brief?

I did, and Hank Greely was an additional author. The scientists who participated in the writing are all active and distinguished researchers at medical schools (including Harvard, Yale, and Johns Hopkins) or universities (including Duke, Penn State, and Kings College, London). They include a former president of the American Society of Human Genetics, a past president of the American Board of Medical Genetics, Fellows of the American Association for the Advancement of Science, and members of the Institute of Medicine and the American Academy of Arts and Sciences.

Why did these law professors, medical and statistical geneticists, and molecular biologists submit an amicus brief?

The brief is intended “to inform the Court of the possible medical and social significance of the DNA data stored in law enforcement databases.” (P. 1). Advocacy groups, legal scholars, and some judges have asserted that the small number of features used in law enforcement DNA databases are predictive of health status (or soon will be). The brief attempts to clarify this issue.

Which side does the brief support?

The brief was submitted in support of neither side. It describes the nature of genetic information, the features of the genome used in law enforcement DNA databases, how those features are used in medical research, and whether they currently permit police, employers, or insurers to discern significant facts about a person’s present or future health status.

What conclusions does it reach?

Amici conclude that “[u]nlike medical genetic tests, law enforcement identification profiles have no known value for medical diagnosis or prediction of future health.” (P. 2).

That’s today. What about the future?

Amici caution that “no one can say with certainty what the future will bring, and it is possible that specific loci will be found to affect the operation of certain genes or to display correlations to disease states.” (P. 2). Nevertheless, they suggest that “it is unlikely that the identification profiles will turn into powerful medical diagnostic or predictive tools that can be used to infer disease states or predispositions by examining forensic database records.” (P.2).

Does this mean that the “CODIS loci,” as the identifying features are called, have no medical significance?

Absolutely not. The DNA sequences have been used in medical research for some 20 years to hunt for disease-causing gene mutations. They have been studied for associations with diseases and traits such as longevity. The question the brief addresses is what kind of information can be gleaned from inspecting a database record.

Doesn’t the highly publicized ENCODE Project prove that there is no such thing as “junk DNA”?

The brief contends that debate over the fraction of the genome that is, in an evolutionary sense, 'junk' ... is orthogonal to the matter before the Court. (P. 26). A section of the brief explains that the data sets and papers recently released from the international Encyclopedia of DNA Elements Project are important to further research into gene regulation and other matters, but they do not indicate that all DNA sequences are critical to health or other important traits. What “[t]he ENCODE papers show [is] that 80% of the genome displays signs of certain types of biochemical activity—even though the activity may be insignificant, pointless, or unnecessary.” (P. 32).

Well, how about other uses? Don’t the CODIS loci tell scientists a lot about a person’s ancestry and race?

Not really. The CODIS loci can reveal something about bio-geographic ancestry, but anthropologists and population geneticists use far more probative ancestry-informative and lineage markers to study genetic histories. That “race” is not a biological category is now well known. As for socially perceived race, “[a] CODIS profile could be used to calculate probabilities that someone would be described as Caucasian, African-American, or Hispanic, but categorical inferences would not be very accurate, and attempts to predict the census-type race of a person from a CODIS profile would seem pointless considering that apparent race already would be known.” (P. 36).

So the brief shows that there is absolutely no important information that can be deduced from a CODIS profile?

No, amici do not say that either. The brief explains that “[b]ecause children inherit all their DNA from their biological parents, the CODIS loci can be powerful tools for determining whether two people could be genetically related as parent and child. ... [T]he most powerful genetic information other than identity that the CODIS profiles contain [would be] that two people are not parent and child” or “that two people were identical twins.” (Pp. 33-34).

Where can I find the brief?

Here is a pdf. It also should appear."soon," along with other briefs, on the American Bar Association's Preview of Supreme Court cases.

Postscript: The brief and an introduction to it is published as Henry T. Greely & David H. Kaye, A Brief of Genetics, Genomics and Forensic Science Researchers in Maryland v. King, 53 Jurimetrics J. 43 (2013). The publication is available at

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