Innocence Blog

Science News: October 3, 2013

Posted: October 3, 2013 11:00 pm

A new collaboration between the Delaware Office of the Chief Medical Examiner and information artist Heather Dewey-Hagborg uses DNA testing to develop facial reconstructions of unidentified persons. While this merger of technology and art may one day help identify individuals and bring closure to families, it begins to blur the line between scientific reliability and artistic interpretation.
 
In a first-of-its-kind field experiment, Dewey-Hagborg is interpreting DNA information to create three- dimensional models of the faces of unidentified victims. She is working with the Delaware Office of the Chief Medical Examiner in the hopes that her work could aid the identification process. Scientists have already determined that our genotype — or the specific sequence of our genetic code — determines our phenotype, or physical identifying traits such as eye color, gender, nose size and skin pigmentation. In other words, our physical appearance is one way our DNA is expressed. Therefore, the new research of Dewey-Hagborg attempts to use DNA testing to access around 50 identifying traits in order to create artistic representations.
 
However, Dewey-Hagborg is correct to quickly explain that her work is based on interpretation and that this idea is not scientifically reliable. Although the scientific community identified the genotype to phenotype link, interpreting and using that data is in the beginning stages. Predicting if a person’s eye color is brown or blue requires testing at six locations in the genotype but is accurate only 90% of the time. While that number may seem reliable, scientists suggest it is not as robust as it sounds — and when 50 or so traits are considered by Dewey-Hagborg, constructing a facial model that resembles what the unidentified person actually looked like proves hypothetical at best. Furthermore, more studies are needed to understand how certain physical traits are linked, meaning that having a specific trait, such as eye color, may increase or decrease the probability of displaying another trait, such as attached ear lobes.
 
It is important to note that the DNA testing done by the Innocence Project to exonerate wrongfully convicted individuals or to identify true perpetrators is different than the testing done by Dewey- Hagborg. The genetic profiles used for identification contain regions of non-coding DNA — or DNA that do not result in any physical trait. Profiles used in identification only examine the sequence of DNA and do not interpret how that DNA will be expressed as physical traits.
 
Even Dewey-Hagborg stated in an interview to Government Technology that she realizes the danger of using DNA testing to experiment with facial modeling, as its use may suggest an “ ‘aura of objectivity because it comes from science.’ ” Her cautiousness is warranted. Misconceptions of science and mathematical probability can influence how the public and courts understand forensic disciplines. For example, the FBI recently announced a review of microscopic hair comparison evidence as examiners gave scientifically invalid testimony regarding the probability of the association of a hair at the crime scene to a person.
 
Ultimately, the discussions about the reliability and validity of the science that underpin Dewey-Hagborg's work are productive; they bring about a better understanding of the limits and pitfalls of the introduction of any new forensic tool.
 
Check out some of the DNA-inspired portraits that Dewey-Hagborg has produced for other projects: http://deweyhagborg.com/strangervisions/portraits.html




Tags: Science Thursday