Detecting homologous DNA sequences in strangers with similar faces

Experts at the Josep Carreras Leukemia Research Institute in Barcelona, ​​Spain studied pairs of unrelated people who looked alike to determine the impact of genetics and environment on their appearance.

They found that the doppelgangers (pairs) in the study not only had similar faces, height and weight, but also had similarities in some aspects of their behaviour.

For decades, the existence of similar individuals without any familial ties has been noticed by science, but without scientific evidence, says researcher Manel Esteller.

The widespread use of the Internet and social networks to share images allows scientists to find and study such people.

32 look-alike pairs in a series of photos by Canadian artist Francois Brunelle completed a questionnaire about their lifestyle and body measurements. Three different facial recognition programs were also used to determine how much each pair looked alike.

Sixteen of them had the highest percentage of face similarity, so much so that all three algorithms determined “they were twins”, when in fact they were strangers.

In addition, the researchers also performed analysis of DNA sequence (genomics), DNA methylation status and microbiome profiles on saliva samples of 16 most similar pairs and found that 9 of them were identical. Some had very similar DNA sequences, but differed in epigenetic DNA methylation patterns and oral microbiota profiles.

Interestingly, the most similar-looking pairs not only shared DNA, but also were very similar in behavioral traits, interests, and lifestyles, such as smoking habits. This suggests that common genetic variation is not only related to appearance but also affects general habits and behaviour.

Some previous studies have compared the genomes of people with facial features, but within the general population, says researcher Esteller. Research by the Josep Carreras Leukemia Research Institute shows that genetic markers are important in the development of the shape of the nose, lips and mouth, bone structure and skin texture.

The findings of this study could open new research directions, provide insights into the genetics of the human face, and have potential applications in biomedicine and forensics, such as reconstruction. Make faces from DNA.

The researchers also suggest that the new finding could help doctors infer a high risk of developing a disease such as diabetes or Alzheimer’s from the features of a gene mutation linked to the face.