Issues in DNA Phenotyping

Far beyond the blood and guts of now, we may be moving on to bigger and better things

Shirley Le
October 24, 2020

DNA profiling has been the standard procedure in forensic science and legal investigation since the 1980s. DNA evidence such as bloodstains and fingerprints can be used to find a match from a government database. Sometimes, however, the database does not provide a comparative profile and DNA evidence becomes a dead-end lead. Science is a never-ending adventure and is full of new discoveries, so it does not surprise the forensic community when next-generation methods arise and have applications in solving cold cases. One of those technologies is DNA phenotyping, which is proving to be both revolutionary and controversial. 

DNA phenotyping involves analyzing the DNA sequences to establish key features of an individual. By collecting DNA samples from many people to add to a database, it is possible to reverse engineer DNA to construct the physical appearance of a person. It involves using statistical calculations to link the genetic variants with the phenotypes by referring to the existing database of genetic information. The combination of science and technology builds an algorithm that can correctly identify a person based on their genetics 74% of the time. Genetic genealogy, using DNA testing and tracing back one’s family tree, is often used in combination with DNA phenotyping.  Several real cases have benefited from this combination to identify both suspects and victims including the murder of a Canadian couple Tanya Van Cuylenborg and Jay Cook in 1987 and the “Golden State Killer”. 

A comparison of the predicted and actual photograph of Rodie Sanchez from the Discovery channel by Parabon Nanolabs

DNA phenotyping’s success rate is low due to many factors. Some physical traits can be artificially altered through the use of coloured contact lenses, hair dye, or even cosmetic surgery. They can also be influenced by the environment a person lives in, so genetics alone cannot determine one’s appearance. A bigger concern that might limit the application of this technology is the potential increase in racial profiling. In the book What’s the Use of Race?: Modern Governance and the Biology of Difference, bioethicist Pamela Sankar criticized DNA phenotyping for its vagueness which makes people of colour more vulnerable to discrimination and stereotyping. However, others argued that the potential bias is less present in a DNA analysis than in eyewitness testimonies. The current justice system already puts people of colour at higher risk, and DNA phenotyping may worsen the problem by contributing to racial profiling. However, it is still a positive development because the possible dangers are not much worse than those presented by previous technologies and methods. 

It’s every police department’s dream to collect DNA evidence and immediately generate a picture of a suspect, and the Toronto Police Service has already submitted several samples from cold cases to private DNA phenotyping services such as Parabon Nanolabs to narrow down possible suspects. DNA phenotyping is still in its early stages but it has already presented promising results. What sounds like science fiction might become reality one day. 


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