It is a known fact that identical twins look alike due to genetics. But what about those unrelated people who also look similar to each other? According to Medical Xpress, a collection of photos of unrelated persons and an analysis of their DNA reveal that substantial facial similarity could be due to some shared genetic variants.

Manel Esteller of the Josep Carreras Leukemia Research Institute in Barcelona, Spain, and a new study co-author, said that their research gives a rare insight into human likeness at the molecular level that shows how people with extreme look-alike faces share common genotypes. However, they have discordant epigenome and microbiome levels that set them apart.

Virtual Twins Who Are Genetically Unrelated But Look the Same

The internet has made it possible for people from different walks of life and parts of the world to connect. That also led to the increased number of people who claim to be virtual twins or doppelgangers by sharing and exchanging pictures online. These are people who look the same but are genetically unrelated.

In the new study titled "Look-Alike Humans Identified by Facial Recognition Algorithms Show Genetic Similarities," published in the journal Cell Reports, Esteller and his team characterized these random human beings who share facial features at the molecular level.

From the photographic work of Canadian artist François Brunelle who has been taking pictures of people who look alike since 1999, the team recruited those people and obtained headshot photos of 32 individuals who seem to share the same facial features. They also used an objective measure of likeness for the pairs that employ three different facial recognition algorithms.

Moreover, the participants were asked to complete a comprehensive biometric and lifestyle questionnaire and then provided saliva DNA to the researchers for multi-omics analysis.

DNA Analysis Revealed People With the Similar Faces Likely Shared the Same Genetic Variants
(Photo : Pixabay/geralt)
DNA Analysis Revealed People With the Similar Faces Likely Shared the Same Genetic Variants

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The results revealed that although these individuals have different DNA methylation and microbiome landscapes, they share identical genotypes. Science Alert reported that the genetic analysis further showed that nine out of the 16 pairs were clustered together by all three algorithms and shared a total of 19,277 common genetic variations in 3,730 genes that accounts for body and facial traits.

Researchers also noted that each participant differed as their microbiome, for instance, was heavily influenced by environmental factors, like nutrition, exercise, and smoking. The same goes for epigenomes that differed even among those ultra look-alikes.

Aside from physical traits, researchers correlated the weight, height, and behavioral traits, like smoking and education, and found that shared genetic variation may also influence common habits and behavior. Estellar said this suggests that the same determinants correlate with physical and behavioral attributes that make up human beings.

Limitations and Implications of the Study

In a similar report in SciTech Daily, researchers also noted the limitations and implications of the study. Its limitations include the small sample size, 2D black-and-white photos, and the predominance of European participants. Nonetheless, the findings provided the molecular basis for future applications.

Such applications could be in forensic medicine, wherein it will allow scientists to reconstruct the criminal's face from DNA and in genetic diagnosis that will give clues as to which genome a person has.

Estellar believes that collaborative efforts will overcome the ultimate challenge of predicting the human face based on the multi-omics landscape of an individual. It could also help predict how a person will look when they grow old.

RELATED ARTICLE: Identical Twins Don't Share the Same DNA All The Time

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