DNA Phenotyping: A New Crime Solving Weapon

Thousands of years ago in a little village in China a farmer was brutally murdered with a harvesting sickle. In a village, where almost everyone owned a sickle, the task of tracing the murder back to the murderer seemed almost impossible. The village chieftain, a scrupulous man, decided to crack the case. He assembled farmers and told them to lay down all their sickles and wait. Some time later the chieftain pointed to the real killer. Upon interrogation the man confessed to the crime.

How did the Chieftain crack it? The sickle belonging to the killer had attracted blow flies. Considering the fact that blow flies can sense blood and dead matter a mile away, and their ability to detect blood traces even if they are thoroughly cleansed.

This was one of the earliest recorded forensic detection. Today, this method of crime solving is known as forensic entomology. It appears that humans have employed science in solving crimes from time immemorial.

Leaping to the present, the modern forensic detection has now come to a stage where pedantic understanding of the surroundings alone is not enough. It calls for confirmatory evidence which is validated scientifically.

We have seen incredible, scientific crime-solving stuff on television, triggering inconclusive debate whether such things are even possible. The truth is, things we thought was a bit of a stretch then have now turned into realized inventions.

One such invention in the world of crime-detection is the DNA Phenotyping. The creators and researchers of this crime solving technique say that the core element of DNA Phenotyping is more of a science than a craft.

How did we arrive at DNA phenotyping?

At the dawn of the twentieth century, Edmond Locard, a forensic expert – the first one to set up a crime lab – formulated a principle, which later turned out to be so valuable that law enforcement agencies around the world adopted and achieved fantastic results. On the other hand, there are groups who still express their concerns over terming Locard’s proposition as a ‘principle’ in a traditional sense. And it continues to be an open discussion, even now. However, Edmond Locard had made an irrefutable point: Every contact leaves a trace.

This principle gave a new twist to forensic detection, and with its advent, crime solving methods slowly evolved and saw several discoveries and inventions such as fingerprint analysis, bite mark analysis, fiber analysis, DNA profiling, and now DNA phenotyping.

So, what is DNA phenotyping?

Though DNA profiling differs from DNA phenotyping, if you understand DNA profiling, then it becomes easier to understand DNA phenotyping.

DNA profiling (also goes by the names DNA fingerprinting, DNA testing and DNA typing) is a method used to identify an individual by matching the DNA samples left by that individual at the crime scene. For example, if you have a suspect at hand and a set of DNA samples at the crime scene, with DNA profiling scientists can say, with a fine degree of accuracy, if the DNA samples belongs to that individual or not.

Okay, so what happens when you don’t have a suspect at hand, but have a set of DNA samples lifted from the crime scene? That’s where DNA phenotyping, as its creators claim, comes to the rescue. This new method helps forensic experts in creating a likelihood of a suspect and creating his/her pictures. DNA phenotyping also goes a step ahead in establishing an individual’s geographic ancestry, track versions of his/her genes, and the facial features too.

According to scientists, different human races are linked to a particular version of genes. DNA phenotyping tracks these versions of genes and scrutinizes the tiny variations of single nucleotide polymorphisms (SNPs), which are spread throughout our genome. The SNPs can reveal a lot about a person, such as the natural hair color, eye color, skin tone, freckled or not, and the type of ear lobe (attached or unattached).

In the US, the researchers at Human Longevity, Inc. and Parabon Nanolabs are trying to maximize the potential of DNA phenotyping by encouraging volunteers to come forward and fill out questionnaires and offer details of their facial features. A 3D scanner captures the facial details like jaw line, face shape, nose, eyes, etc., and are stored in huge databases.

How does it work?

A DNA sample is found at the crime scene, but the law enforcement hits a dead-end as it does not match with any of their list of suspects.

Enter DNA phenotyping. The genetic sample, collected from the crime scene, is converted into a code and goes through a rigorous process using complex computer algorithms.

The thousands of 3D facial scans of volunteers stored in the database help predict and throw up most likely statistic percentages of physical traits such as, race (Asian, European, Middle Eastern, American, African), Eye color (black, hazel, brown, blue), hair color, skin tone etc.

It builds a computer-generated 3D facial composites with the most likely jaw line, type of nose, forehead, shape of face and so on.

The end result. A finely reverse-engineered three dimensional face.

Here’s an example. We have seen the law extracting information about a murderer or criminal from an innocent bystander. The bystander goes about explaining what the killer looked like while an artist would sketch taking cues from the bystander, and bring out a portrait of a killer who is likely to be the killer.

With DNA phenotyping, that ‘bystander’ and ‘artist’ is replaced by a more reliable source - DNA samples, genes, SNPs, and complex computer algorithms to reverse engineer and give a face to an individual who is most likely the perpetrator. This gives the law enforcement something to propel their investigation.

Now, the law enforcement will have something to propel their investigation.

As mentioned earlier the DNA phenotyping heavily relies on samples of facial features provided by volunteers (to study the SNP patterns). But a country like India, with a polygenic population, and with such a diverse race and culture, this facial scan collection is going to be a humongous task, that is if India decides to adopt DNA phenotyping.

Is Forensic Science Flawless?

The creators of DNA phenotyping, and the researchers at Prabon.Inc, US, stress that the DNA phenotyping is not indented to identify a suspect, but to narrow down the search to such an extent that it eliminates the ones who are not related to that crime.

And it’s not hard to see why they stress this point so much. The forensic science had held sway for decades, however, over recent times it had come under the eyes of scrutiny, questioning it’s perfection and validity. In the US, sometimes, the forensic evidence are over-stuffed in courtrooms, and since the understanding of forensic science is beyond the purview of common people, bungled analysis has led to several wrong convictions and prosecutions, sending innocent people to be locked away in prisons for crimes they did not commit.

Forensic science, contrary to popular belief, is not just about fancy gadgets. It is a practice that calls for an equal participation of human intelligence. Now, it so happens that several forensic experts agree that forensic science is only as good as the expertise of its practitioners, it had created a compelling reason to question its reliability.

Of course, DNA phenotyping has its own downside. Not all human aspects are encoded in the DNA, as if they had a mustache or beard, if they colored their hair or not. We can only hope that, with the help of science, these unturned stones would be turned soon.

Nonetheless, crime busters are rolling up their sleeves and are revisiting cold cases with renewed enthusiasm, hoping that the new method – DNA phenotyping – could help them resurrect cases and solve them.

It’s an irrefutable fact that science had helped crime busters in solving some of the most baffling cases in history. With science intertwining so rapidly in crime solving, we can only hope that DNA phenotyping flawlessly does what it set out to do.