On the web it is increasingly easier to identify virtual twins or doubles. There is perhaps a scientific explanation for this, as a study published in Cell Reports illustrates
Who looks alike, takes it, says the proverb. Popular wisdom tries to explain the law of attraction between people on the basis of physiognomy. But the science goes further: thanks to the use of facial recognition algorithms, strong facial similarity could be associated with shared genetic variants. This, at least, is what emerges from a study published in Cell Reports by the group of researchers led by Manel Esteller of the Josep Carreras Leukemia Research Institute in Barcelona. Our study – explains Esteller – provides a rare insight into human similarity, showing that people with extremely similar faces they share common genotypes, while they are discordant at the epigenome and microbiome level
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Characterizing human beings at the molecular level
The number of people identified online as virtual twins or doubles which are genetically unrelated increased due to the expansion of the World Wide Web and the possibility of exchanging images of human beings all over the planet. In the new studio, Esteller and his team have decided to characterize, at the molecular level, randomly selected human beings who objectively share facial features.
To do so, they recruited human lookalikes from the photographic work of François Brunelle, a Canadian artist who has been obtaining lookalike images around the world since 1999. They have obtained face photo of 32 lookalike couples. The researchers determined an objective measure of similarity for the couples using three different facial recognition algorithms. Additionally, the participants completed a biometric and lifestyle questionnaire complete and have provided the
Saliva DNA for multiomics analysis. This unique set of samples allowed us to study how genomics, epigenomics and microbiomics can contribute to human similarity, Esteller says.
Half of the couples examined, also similar in habits and behavior
Overall, the results revealed that these individuals share similar genotypes, but they differ in the methylation (epigenetic modification) of DNA and in the landscapes of the microbiome. Half of the look-alike pairs were placed in the same group by all three algorithms. Genetic analysis revealed that 9 of these 16 pairs were groupedbased on 19,277 common single nucleotide polymorphisms.
Furthermore, physical traits such as weight and height, as well as behavioral traits such as smoking and education, were correlated in look-alike pairs. Taken together, The results suggest that the shared genetic variation not only affects a similar physical appearance, but may also influence common habits and behaviors. We have provided a unique insight into the molecular features that potentially influence the construction of the human face, Esteller says.
The limits of the study
However, the study has some limitations, as the authors themselves admit: the sample examined was small, 2D black and white images were used and the participants are mostly European. Nonetheless, the findings could provide a molecular basis for future applications in various fields such as biomedicine, evolution and forensics.
These findings will have future implications in forensics, reconstructing the criminal’s face from DNA, and in genetic diagnosis: the photo of the patient’s face will already provide clues as to which genome he has, Esteller says. Through collaborative efforts, the ultimate challenge would be to predict the structure of the human face on the basis of the individual’s multiomic panorama.
The facial features are largely influenced by the environment
Ma really people with similar faces probably have similar DNA? In a sense, yes – he answers Gian Gaetano Tartaglia IIT researcher and head of the “RNA Systems Biology” laboratory -. The facial features are largely influenced by the environment. Often people with similar faces have a common genetic background. This is because living in a certain environment, for example at the North Pole or the Equator, leads us to have a certain cut of the eyes, skin color, propensity to baldness and so on. Essentially we must consider that the expression of genes (ie the number of copies of Rna that a cell produces for a given gene) determines the growth of tissues, and It is quite likely that those with the same mutations, or SNPs, may have a similar facial oval, or a comparable nose….
Pioneering research but with reservations
How reliable can such a study be? Definitely a “pioneering” study because it connects an external property like appearance with something internal like DNA. There is a question that is a little discouraging: images of similar couples, originally collected from men, are recognized by algorithms only in 50% of cases.
This means that our ability to be physiognomists is not absolutely objective, or at least men classify differently from computers. Perhaps we should also consider that the algorithms are not perfect. So that ability to find similarities, all human, difficult to measure (and consequently, also the similarity of DNA is not easily ascertainable), says the expert.
The limit of belonging to the same ethnic group
What are the weaknesses, in addition to those highlighted by the authors? it is easy to find similarities in the same population, and this is the weakest point: the double is an individual who comes from the same ethnic group. The fact that my duplicate is ethnically similar helps to make lifestyle statistics (to smoke, to drink, to live long, etc.), but not currently useful for finding more detailed information (cancer, neurodegeneration, etc). In other words, the classification is neither accurate nor effective for developing other aspects, such as preventive medicine, continues.
Let’s see it from a more detailed point of view. Our children look like us because they have the same mutations, or SNPs. Many mutations or SNPs do not occur only in the family, but also in the population where the ethnic group lives (a sort of “super familia”). For this reason ethnic groups that have been isolated and that have not traveled to other places are well defined, even morphologically. The similarity of those who live in the same environment is sure.
The classic example is sickle cell anemia which is abundant in Sardinia. Interestingly, the epigenome (ie, chemically modified DNA) and bacterial population cannot be used to classify similar individuals, indicating that a considerable level of complexity is due to the environment. We know that bacteria have a huge influence on the development of some diseases (think of the Helicobacter Pylori bacterium and stomach cancer for example), so the classification is really difficult.
Precision medicine on the fly
And what could be the possible scientific implications, the benefits for people but also the risks that relying on algorithms in such a delicate field can cause? Being able to measure genetic properties based on appearance has always been a dream. The greatest benefit would be to make some sort of precise “on the fly” medicines, collecting common characteristics between individuals through algorithms. Knowing if an individual develops heart disease, one could for example prevent his duplication (prostate cancer, etc)… Various attempts have been made in the past for connect the common characteristics of individualsSuffice it to recall Cesare Lombroso and the classification of criminals based on the shape of the skull, but now the quantification of fa is now more objective. And it will become more accurate as the collected genome samples become more abundant.
The cultural aspect of it scares me a little. Part of the article shows that similar people also have the same educational background. dangerous to think that people are predetermined in their studies based on physical characteristics. The social aspects, that is the interactions between individuals, mainly families (but not only) influence our choices every day. We cannot speak of predetermination.
August 23, 2022 (change August 23, 2022 | 17:48)
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