Doubles do exist. And they don’t just look alike

Everyone has a doppelganger, they say. It may be a bit exaggerated, but they exist. And they share more than their looks. This emerges from a DNA analysis of sixteen very similar duos.

Photographs by Canadian artist François Brunelle were used to obtain the lookalikes. He has been collecting photos of very similar people since 1999. Spanish scientists from the Josep Carreras Leukemia Research Institute (IJC) in Barcelona, ​​three facial recognition algorithms examined 32 extremely similar pairs. Sixteen of them have been classified as look-alikes. After genetic analysis, nine were found to be even more similar. These “super doubles” shared more than 19,000 genetic variations in 3,730 genes. Most of the genes were linked to facial and body characteristics. But there’s more: the doppelganger’s responses to detailed questionnaires indicated that they shared a number of other characteristics as well.

Nature versus culture
“These findings not only provide insight into the genes associated with our appearance, and likely other traits of our body and personality, but also highlight just how much of who we are and what defines us is truly inherited or acquired during our lifetime,” write the authors.

“In 2005, we discovered that twin brothers with the same DNA were not epigenetically the same. That is, there were chemical changes in the DNA sequence that regulate gene expression. That explained why they weren’t perfectly identical. In the current study, we looked at the other side: people have the same face, but are not related to each other. These people help us answer the question of how much our appearance is determined by nature rather than nurture,” said lead researcher Manel Esteller. Scientias.nl.

“We tried to analyze as many molecular layers as possible in the samples available. In this case, DNA was the most stable component. We were able to determine the DNA sequence (genome), DNA methylation (epigenome) and bacterial and viral content (microbiome). All three components are decisive in determining the activity of cells and tissues.

Complex properties in common
Esteller explains that the genes the doppelgangers shared fell into four categories. “It involved genes associated with the shape of the eyes, lips, mouth, nostrils and other parts of the face, genes involved in bone formation, such as the shape of the skull, genes that determine the type of skin and genes that influence the amount of moisture you retain, leading to a different volume and appearance of a face.

But the doppelgangers had more in common. “The couples with the shared genetic variants not only had extremely similar faces, but they were also roughly the same height and weight. They also shared more complex traits, such as their smoking behavior, level of education and whether they were left-wing or right-wing.

Still with family?
Perhaps the lookalikes are distant relatives, the researchers wondered. “We’ve done genetic research that goes back generations and these individuals aren’t even remotely related, there’s no common ancestor. They just happened by coincidence. There are so many people on the planet that the system begins to produce individuals with many common genetic variants,” Esteller said.

It seems logical, but the researcher was certainly surprised by the results. “At the start of the study, I thought the environment would have a stronger influence on the face, but the genes seem to be stronger in this study.”

Criminal designs
His discoveries can be applied in several fields. “The study enables the development of a new artificial intelligence that can help diagnose genetic diseases. We can deduce from facial features the presence of genetic mutations linked, for example, to a high risk of diseases such as diabetes or Alzheimer’s disease. The results can also be used in forensics, as we now know specific genetic variants that determine facial features, and so we can draw a face from an unknown DNA sample,” Esteller said.

So this rare doppelganger turns out to be extremely useful. But people who look so much alike are not very common. Researchers had to search for a long time. If you meet your doppelganger, be sure to contact them, not just for the science, but because you probably have more in common than you think.