Charlie Chasen and Michael Malone met in Atlanta in 1997, when Malone guest-starred in Chasen’s band. They quickly became friends, but they didn’t realize what people around them saw: the two could pass for twins.
Malone and Chasen are “doppelgängers” in German. They are incredibly similar, but not related. His immediate ancestors aren’t even from the same part of the world: Chasen’s ancestors came from Lithuania and Scotland, while Malone’s are from the Dominican Republic and the Bahamas.
The two friends, along with hundreds of other unrelated look-alikes, participated in a photography project by Canadian artist François Brunelle. The image series “I’m Not a Lookalike!” was inspired by Brunelle’s discovery of her own lookalike, the English actor Rowan Atkinson.
The project was successful on social media and other parts of the internet, but it also caught the attention of scientists who study genetic relationships. Doctor Manel Esteller, a researcher at the Josep Carreras Leukemia Research Institute in Barcelona, Spain, had previously studied the physical differences between identical twins and wanted to examine the reverse: people who look alike but are not related. “What’s the explanation for that?” he asked himself.
In a study published Tuesday in the journal Cell Reports, Esteller and his team recruited 32 pairs of look-alikes from Brunelle’s photographs to take DNA tests and fill out questionnaires about their lifestyles. The researchers used facial recognition software to quantify the similarities between the participants’ faces. Sixteen of these 32 pairs achieved overall scores similar to identical twins analyzed by the same software. The researchers then compared the DNA of these 16 pairs of “doppelgängers” to see if their DNA was as similar as their faces.
Esteller found that the 16 pairs that were “true” look-alikes shared significantly more genes than the other 16 pairs that the software found less similar. “These people really look alike because they share important parts of the genome, or the DNA sequence,” he said. That people who look more alike have more genes in common “may seem like common sense, but it’s never been demonstrated,” he said.
There seems to be something very strong in terms of genetics that is causing two similar individuals to also have similar profiles across the genome.
DNA alone, however, does not tell the whole story of our makeup. Our lived experiences and those of our ancestors influence which of our genes are turned on or off — what scientists call epigenomes. And the microbiome, our microscopic co-pilot made up of bacteria, fungi and viruses, is even more influenced by the environment. Esteller found that while the doppelgängers’ genomes were similar, their epigenomes and microbiomes were different. “Genetics bring them together, and epigenetics and the microbiome separate them,” he said.
This discrepancy tells us that the pairs’ similar appearances have more to do with their DNA than the environments in which they grew up. This surprised Ester, who had expected to find a greater environmental influence.
As the appearance of “doppelgängers” is more attributable to shared genes than shared life experiences, this means that, to some extent, their similarities are just chance, brought about by population growth. After all, there are a limited number of ways to build a face.
“Today there are so many people in the world that the system is repeating itself,” Esteller said. It’s not unreasonable to assume that you might have a doppelganger out there, too.
Esteller hopes the study’s findings will help doctors diagnose disease in the future — if people have enough similar genes to look alike, they may also share disease predilections.
“There seems to be something very strong in terms of genetics that is causing two similar individuals to also have similar profiles across the genome,” said Olivier Elemento, director of the Englander Institute for Precision Medicine at Weill Cornell Medicine in New York, who did not participate in the study. Discrepancies between DNA predictions and people’s actual appearance could alert doctors to problems, he said.
Translated by Luiz Roberto M. Gonçalves
