If you are into the crime and investigation genres of movies and TV, you probably understand how challenging and complicated the entire investigative process actually is. It all starts with the collection of evidence and the thorough examination of a crime scene, and only after following a series of protocols and gathering of information can one successfully apprehend the perpetrator.
However, what if one could reconstruct the very face of the perpetrator just from a DNA sample found at the crime scene?
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Among all the methods of facial reconstruction that have been around for the past few decades, nothing is as impressive and accurate as DNA Phenotyping. This is basically the process of predicting an organism’s phenotype (i.e., a composite of an organism’s traits, including physiological and biochemical properties, behavior and its effects) that is collected from DNA sequencing of their sample.
For all non-biologists out there, DNA sequencing helps to determine the exact order of nucleotides within a DNA molecule of an organism, which can subsequently give incredible insights into its biological profile. DNA sequencing has a number of applications in the areas of biology, medicine, forensics and other medical domains.
Also referred to as molecular photofitting, DNA Phenotyping has a number of applications, but it is mainly used for determining a person’s facial attributes for forensic and investigation purposes.
How they reconstruct human faces using DNA samples
When translating a select few biomarkers collected from a DNA sample into meaningful predictions regarding its source, single nucleotide polymorphism or SNP is used. The term ‘SNP’ is used to refer to a variation at a single site in the DNA of an organism, which also happens to be the most frequent type of variation in the genome. Take a look at this picture for a better understanding of SNP:
Notice the difference between the upper and lower DNA molecules? This difference can influence an array of things related to human bodies, such as how susceptible a person may be to certain diseases, how a person’s body might respond to certain treatments and so on. Furthermore, it can also help in obtaining both phenotypic (traits and characteristics) and genotypic (genetic content) data from an individual. Here’s a paper discussing in detail the applications of SNPs in forensics.
The genotyping lab creates a SNP profile (basically a DNA blueprint) that has plenty of data pertaining to the data sample. However, the data that is subsequently obtained is little more than mumbo-jumbo until it is analyzed by various data models and algorithms to extract meaningful information pertaining to the genetic and physical traits of the subject. As of now, such technological solutions are provided by private companies (like Parabon NanoLabs), which offer such services when contacted by law enforcement agencies.
How is DNA Phenotyping different from DNA Profiling?
As their names signify, both DNA profiling and DNA phenotyping use DNA for identification and forensic purposes. However, authorities use DNA profiling (like fingerprinting) to ‘identify’ an individual when they already have their hands on the DNA sample of a potentially matching individual. However, when there is nothing to go on, DNA phenotyping can help to establish what the perpetrator might look like and then narrow down the pool of suspects even further. It’s only after DNA phenotyping that DNA profiling essentially enters the investigation scenario.
DNA phenotyping can greatly help in ascertaining the identity of perpetrators when investigators have very few clues to go on. If they can accurately establish even a few facial traits of the perpetrator, it can significantly narrow down the list of suspects and speed up the investigation process. In the future, our understanding of human DNA will be even greater, and we will be able to reconstruct even more detailed facial features than we do now with DNA phenotyping.