By Min Luo
In a crime scene, detectives may trace potential suspects with just a strand of hair. Then in the high-tech lab, forensic officers extract DNA evidence that points to a suspect. This is a typical scenario in crime TV shows.
However, that is the best scenario. In reality, even with DNA collected from the crime scene, investigations descend into deadlock if there is no suspect available to compare or no match found in the DNA database.
The uniqueness of DNA makes it powerful in crime investigation. What else can it tell us?
UTS researcher Dr Mark Barash is conducting human DNA profiling research to explain the genes responsible for the shape and size of our facial features. The aim is to develop more accurate methods of facial reconstruction to help identify victims of natural disasters and solve cold cases.
His research is trying to fill in the gaps where the DNA evidence could not work at its best. Dr Barash has experienced the strengths and weaknesses of the current DNA profiling in identifying suspects and victims of natural disasters. Now he is going to “convince” the DNA molecule to “talk”.
Dr Barash has collected DNA samples and 3D facial images from almost 600 volunteers; over 100 craniofacial measurements were collected through graphic software after analysing the facial images. The result shows associations between ‘bits’ (single nucleotide polymorphisms) and craniofacial traits, which may allow the prediction of a person’s appearance from a DNA sample in the future.
Many prior studies have indicated that the shapes and traits that make each human face unique are dependent on genes. At the current stage, only hair, eye and skin color, as well as ethnic background, are relatively easy to identify. And these findings have already been used by law enforcement. For example, in the 2004 Madrid bombings, forensic officers predicted the suspect was from North Africa from the DNA extracted from the scene.
Facial reconstruction from DNA is another matter. According to Dr Barash, firstly, genes that affect the size and shape of the facial features are largely unknown. Secondly, each gene has a small bit of influence on the face and the influences are affected by many factors, such as the outside environment and eating habits for example, which required detailed and complex study. Furthermore, large-scale of samples are needed to cover different populations, different backgrounds so as to guarantee statistical reliability.
Despites the important value of the research in scientific and forensic fields, the dispute over the DNA analysis never ends. In 2012, American artist Heather Dewey-Hagborg created human faces from the DNA she extracted from discarded items like cigarette butts, chewing gum and hair, and exhibited them in her ‘Strange Visions’ 3D exhibition, aiming at arousing public awareness on the downside of DNA analysis.
As the most unique information for an individual, DNA
can be used by law enforcement for legitimate purposes, just like Dr Barash’s study. However, it may also be used for commercial and other purposes which may violate personal privacy.
However, as Dr Barash says, “current DNA analysis could only predict some facial features, not the whole face”. He emphasises that the samples collected are solely used for scientific purpose, and they are all “de-identified”.