Do you have a secret twin? Strangers with similar faces share many gene variants

BARCELONA, Spain — Your face is a genetic puzzle — that someone else may be sharing as well! A new study finds unrelated people with similar facial features likely share many of the same genetic variants.

The findings are based on photos of genetically unrelated lookalikes, along with a DNA analysis. Researchers say it could lead to screening patients for illness and even improvements in crime-solving through DNA testing. It may make it possible to reconstruct a suspect’s face through the hair, skin, or bodily fluids they leave at the scene.

“These results will have future implications in forensic medicine—reconstructing the criminal’s face from DNA—and in genetic diagnosis—the photo of the patient’s face will already give you clues as to which genome he or she has,” says senior author Professor Manel Esteller from the Josep Carreras Leukemia Research Institute, in a media release.

The study, published in the journal Cell Reports, linked mutations with individual traits, such as head width and nose and lip size.

“Our study provides a rare insight into human likeness by showing that people with extreme lookalike faces share common genotypes, whereas they are discordant at the epigenome and microbiome levels,” Esteller continues. “Genomics clusters them together, and the rest sets them apart.”

Social media is making it easier to find doppelgangers

The number of people identified online as doppelgangers — virtual “twins” who are not family relatives — has increased due to the expansion of social media. Pictures of humans can be exchanged across the world, enabling characterization on a molecular level of random human beings who resemble each other.

Study authors obtained headshots of 32 couples from Francois Brunelle, a Canadian artist who has been researching lookalikes since 1999. The researchers determined an objective measure of likeness for the pairs using three different facial recognition algorithms.

In addition, the participants completed a comprehensive biometric and lifestyle questionnaire and provided saliva DNA for multiomics analysis.

“This unique set of samples has allowed us to study how genomics, epigenomics, and microbiomics can contribute to human resemblance,” Esteller explains.

Similar genes may also lead to similar behavior

Overall, the results revealed the individuals share similar genotypes, but differ in their DNA methylation and microbiome landscapes. Half of the lookalike pairs were clustered together by all three algorithms. Genetic analysis revealed that nine of these 16 pairs clustered together, based on 19,277 common mutations.

Moreover, the team linked physical and behavioral traits such as weigh, height, smoking, and education history between the lookalike pairs. Taken together, the results suggest shared genetic variation not only relates to similar physical appearance but may also influence common habits and behavior.

“We provided a unique insight into the molecular characteristics that potentially influence the construction of the human face,” Esteller adds. “We suggest that these same determinants correlate with both physical and behavioral attributes that constitute human beings.”

The findings may provide a molecular basis for future applications in various fields such as biomedicine, evolution, and forensics.

“Through collaborative efforts, the ultimate challenge would be to predict the human face structure based on the individual’s multiomics landscape,” the study author concludes.

Previous research has identified genes that influence the extraordinary variation in the human face. Scientists hope police will soon be constructing more accurate faces of dangerous criminals still at large through these genetic clues.

South West News Service writer Mark Waghorn contributed to this report.