Because of their faces, they not only look like twins, but they also have similar bodies and similar habits.
The existence of “doubles & rdquor; between people who are not family has multiplied with population growth and new research has found that they not only share similar physical traits, but also DNA, habits and behaviors. However, they differ in how their lives impact their respective genomes.
An investigation carried out at the Josep Carreras Leukemia Institute in Barcelona and directed by Dr. Manuel Estellersuggests that people who share similar physical traits may have similar DNA.
In an article published in the journal Cell Reports, the authors of this research explain that the human face is one of the most visible features of our unique identity as individuals.
They note that monozygotic twins share nearly identical facial features and the same DNA sequence, but may show differences in other biometric parameters.
They also draw attention to another no less surprising phenomenon: for decades, the existence of individuals who resemble each other without there being any family bond between them (known as “doubles & rdquor ;, “look-alike & rdquor; in English or “doppelgänger & rdquor; in German ) has been described as a proven fact, but anecdotal and without any scientific justification.
duplicate humans
However, the irruption of the internet and social networks has caused thousands of personal photographs to be shared all over the world and has shown that the existence of “copies & rdquor; between the faces of people who are not family is more frequent than previously thought.
The new research has characterized in detail a set of “look-alike” humans, defined by facial recognition algorithms, for their multi-omic landscape. He has found that these individuals share similar genotypes and differ in their DNA methylation and microbiome landscape.
The results revealed that human doppelgangers share similar variations of their DNA, particularly in relation to genes involved in the formation of the mouth, nose, eyes, chin and forehead.
But the similarities go far beyond the face, as Dr. Esteller points out in a statement: “It was curious to see that the resemblance of these double pairs was not only limited to facial features, but, in addition to affecting other physical properties (height and weight), also extended to certain traits of character and behavior & rdquor ;.
Increasingly
Esteller considers that this study can open new lines of research in the future in various fields and highlights that, on the one hand, “it provides the basis for diagnosing genetic diseases from the analysis of the image and the shape of the face” and, on the other, “it would allow the reconstruction of the face of an unknown person from only a DNA sample, one of the great challenges of forensic medicine and criminalistics & rdquor ;, concludes the researcher.
He adds that since the human population now stands at 7.9 billion and is much more interconnected, it is becoming more and more likely that these repetitions will occur and be known. “Now there are so many people in the world that the system is repeating itself & rdquor ;, considers Esteller, quoted by The New York Times.
The study was based on 64 look-alike photographs, along with saliva lifestyle and DNA questionnaires for each participant, as well as DNA analyzes of 16 look-alike couples.
Three different facial recognition algorithms scored the resemblance of 32 pairs of similar people, of which half were classified as doubles by the algorithms. The researchers then performed genetic analyzes and found 9 very similar pairs.
Together, these super doubles share 19,277 common genetic variations in 3,730 genes, many of which have to do with body and facial features.
shared things
The personal questionnaires to which they were also subjected suggest that they share much more. Some lifestyle characteristics, such as smoking habits, weight and level of education, were also associated with many similar couples.
However, individual participants differed in how their life impacted their genome. Each person’s microbiome, for example, is strongly influenced by environmental factors such as nutrition, exercise and smoking, the researchers noted. This means that the intestinal flora differs greatly from one individual to another, even among those who have similar genetics.
The same goes for the epigenome of each double, which describes the chemical modifications made to the coiled-up strands of DNA that can turn genes on or off. These differed even among the ultra-similar in the current study.
It is true that the sample size is small, but the results, according to the authors, are “surprising”.
Reference
Look-alike humans identified by facial recognition algorithms show genetic similarities. Ricky S. Joshi et al. Cell Reports, Volume 40, Issue 8, 111257, August 23, 2022. DOI:https://doi.org/10.1016/j.celrep.2022.111257