There may be someone on this planet who looks just like you. Even if you’re not twins, you likely share a lot of your DNA, a new study suggests.
Charlie Chasen and Michael Malone met in Atlanta in 1997. Malone had been invited into Chasen’s band to sing. They quickly became friends, but what they hadn’t noticed, unlike the people around them, was that they could pass for twins.
Malone and Chasen are lookalikes. They look alike like two drops of water, but they are not related. Their immediate ancestors don’t even come from the same region of the world: Chasen’s family hails from Lithuania and Scotland, and Malone’s from the Dominican Republic and the Bahamas.
The two friends, as well as hundreds of other look-alikes, took part in a photographic project, led by Canadian artist François Brunelle. The idea of the series entitled I am not a double! sprouted when Brunelle discovered he was the spitting image of English actor Rowan Atkinson.
This project has had great success on social networks and more widely on the Internet, but it has also attracted the attention of scientists who study genetics. Manel Esteller, a researcher at the Josep Carreras Leukemia Research Institute in Barcelona, Spain, had previously studied the physical differences between identical twins, and he wanted to examine another situation: people who look alike but have no family relationship. This phenomenon intrigued him.
According to a study published on Tuesday [23 août] in the scientific journal Cell Reports, Manel Esteller and his team recruited 32 pairs of look-alikes immortalized in Brunelle’s photos to analyze their DNA and submit complete questionnaires on their way of life. The researchers used facial recognition software to count the similarities between the faces of the participants. Sixteen of these 32 couples obtained scores similar to identical twins analyzed by the same software. The researchers then compared the DNAs of these 16 pairs of look-alikes to see if their DNA, too, was identical.
Manel Esteller’s team discovered that the 16 pairs of look-alikes who were from “true” look-alikes had far more genes in common than the other 16, which were less alike according to the facial recognition software. “These people really look alike because they have a significant amount of common genome, that is, DNA sequence,” ehe explains. That people who look alike have more genes in common “may seem logical, but it had never been demonstrated”, he continues.
Unknown element
However, DNA alone cannot explain everything. The experiences we have had, and those of our ancestors, influence the activation of our genes – this is what scientists call the “epigenome”. And our microbiome, our microscopic co-pilot made up of bacteria, fungi and viruses, is influenced even more by our environment. The researcher found that while the lookalike genomes were similar, their epigenomes and microbiomes were different. “Genetics bring them together but epigenetics and the microbiome keep them apart”, he observes.
There are not so many ways to build a face
The resemblance of these look-alikes therefore has more to do with their DNA than with the environment in which they grew up. This surprised Esteller, who expected to find that the environment played a very important role. And since the resemblance of these doppelgangers is due more to shared genes than to similar life experiences, it means that, to a certain extent, their resemblance is just a matter of chance, linked to the growth of the population. After all, there are not so many ways to build a face.
“There are so many people on Earth right now that the system is repeating itself,” forward Manel Esteller. It is therefore not unreasonable to think that we all have a look-alike somewhere.
Manel Esteller hopes the findings from this study will help doctors diagnose diseases in the future – if people have similar genes, they may also share a predisposition to certain diseases.
“There is apparently some conclusive genetic evidence that two individuals who look alike also have similar genomic profiles,” acknowledges Olivier Elemento, director of the Englander Institute for Precision Medicine at Weill Cornell Medical School in New York, who was not involved in the study. Discrepancies between DNA predictions and people’s actual appearance could help doctors spot problems, he believes.
Manel Esteller also suggests that there may be links between facial features and behaviors, and that the findings of this study may one day allow forensic scientists to establish a composite portrait of a suspect. only from samples of his DNA. However, Daphne Martschenko of the Stanford Center for Biomedical Ethics, who was not involved in the project, advises caution before applying these findings to forensic science.
The researcher recalls:
“We have already seen many examples of the damage wrought by facial recognition algorithms that have only reinforced existing racial biases in housing and recruitment and in criminal profiling.”
According to her, this study “raises a large number of ethical questions”.
Despite the risks posed by this correlation between how people look and their DNA or behavior, Charlie Chasen and Michael Malone say the photographic project – and the knowledge that we all might have a “secret twin” somewhere – had beneficial effects. The two men have been friends for twenty-five years, and when Chasen planned to marry, Malone was the first to know. If all the people whose DNA is alike do not share such a complicity, Malone assures that François Brunelle’s project is “another way to bring us all together, as human beings”.