By Mark O’Brian

Recently, the U.S. Supreme Court ruled that it is constitutional to acquire and analyze DNA from anyone arrested for a serious crime. The five-justice majority argued that this evidence is used for identification of the suspect, and therefore it is no different from taking fingerprints or photographs. Regardless of one’s view on the use of DNA as evidence, it is incorrect to equate it with traditional means of identification.

The DNA genome is a fingerprint of our entire physical being that far exceeds the superficial description of the skin found at the tip of each digit. Because DNA is inherited, it is a historical document that contributes to unraveling the story of the geographical origins of our ancestors, the social interactions between different ethnic groups and even whether our ancestors arrived in this country by choice or by force.

DNA is also predictive because it can provide clues into the physical traits of children not yet born or the likelihood of developing a disease. It is almost silly to equate this vast narrative over time to a mug shot, which is merely a camera’s perspective of a human head at a particular moment on a given day.

As advances in technology are made, it is becoming easier and cheaper to decode the encrypted DNA. It will soon become routine to determine the entire sequence of a person’s genome and the interpretation of that sequence continues to improve. In principle, new information can be obtained from DNA databases years after an arrest, regardless of guilt. This cannot happen with photographs and fingerprints.

These improved methodologies will likely make it possible to determine the genetic contribution of behavioral propensities such as nurturing, aggression and, yes, criminality. Although discovery of a “criminal gene” is unlikely, the complex combination of multiple genes and the environment that contribute to increased susceptibility will be at least partially uncovered. To use a genetic tendency as trial evidence would be akin to prosecuting a thought crime.

In context of the Supreme Court ruling, an important question is whether DNA taken directly from a person without consent will at some time be used, legally or otherwise, for things other than identification. The optimistic answer is no, but a more realistic answer is that we do not know. The application of knowledge and technology once obtained is difficult to resist. Regardless, the rationale for the majority decision is wrong because it fails to acknowledge the vast information in the genome that can identify us in ways that are not currently intended or known.

As an educator, I find great satisfaction in teaching the beauty of science to bright, curious minds. Right now I can think of five students I would love to have in my class.

Mark O’Brian is a professor of biochemistry at the University at Buffalo, and has considerable experience with DNA analysis.