August 30, 2022 – Most people have played the “separation at birth” game, joking that similar friends and even unrelated celebrities may have secret joint paternity.
But new research shows it’s no kidding that with some similar people, there’s actually more to idea than meets the eye. eye. A team of Spanish scientists studied pairs of unrelated homosexuals and found that they not only look amazingly similar to each other, but also share important parts of their DNA.
The results are published in the journal cell reportsWe suggest that these genetic similarities may extend beyond mere facial appearance. Researchers say DNA analysis based on the new work could one day help clinicians determine a person’s hidden risks for certain diseases, and even help law enforcement officials target criminals with biometric forensics.
But perhaps the most wonderful takeaway is the possibility that most people on this planet have an unrelated “twin” somewhere, Says Manil Esteler, Ph.D., researcher at Josep Carreras blood cancer The research institute in Barcelona who led the study.
“It’s not unreasonable to assume that you, too, might have a similar appearance there,” he says.
Esteller’s new study stems from his research into the similarities and differences between identical twins. Inspired by a French-Canadian artist’s photography project Francois Brunelwho has been taking photos of his unrelated looks all over the world since 1999. His gorgeous photos have prompted Esteller to wonder: Can DNA explain these two similar ‘twins’?
“We discovered in 2005 that fraternal twins have the same DNA [also called monozygotic twins] Introduce epigenetic differences [chemical changes in DNA that regulate how genes are expressed] This explains why they are not completely identical.”
“In the current study, we explored the other side of the coin: people who have the same face, but are not close relatives. These individuals helped answer the long-standing question of how our side is determined by nature and/or nurture.”
To answer this question, Esteller’s team recruited 32 pairs of people from Brunelle photo sessions to take DNA tests and complete lifestyle questionnaires. The researchers also used facial recognition software to assess facial similarities from head images.
They found that 16 of the identical pairs had scores on par with those of true identical twins, who were also analyzed by the team’s facial recognition software. Among the similar pairs, 13 were of European descent, one of Hispanic, one of East Asian, and one of Central and South Asian.
The researchers then examined the DNA of those 16 similar pairs and found that they shared significantly more of their genetic material than the other 16 pairs that the program deemed less similar in appearance — a finding the researchers said was “stunning.”
Esteller notes that it appears to be “common sense” for people who look like them to share “significant parts of the genome, or DNA sequences,” but this has not been scientifically proven — until now, that is the case.
“We found that the genetic loci shared by the similar person corresponded to four categories,” he says. “Genes previously reported to be associated with the shape and appearance of the eyes, lips, mouth, nose and other parts of the face using general population studies; the genes involved in bone formation that can be associated with the shape of the skull; genes involved in outstanding skin texture; [and] Genes involved in fluid retention which can give our face different sizes.”
While the doppelgangers’ DNA was closely matched, Esteller was surprised to discover that lifestyle surveys — evaluating 68 variables — revealed significant differences in 16 pairs of people. These differences were almost certainly due to the environment and other parts of their lives and upbringing (think: “nurture versus nature”) that had nothing to do with their genetic makeup.
These differences, he explains, are another sign that the similarities in the appearance of pairs have more to do with shared DNA than other things.
However, it was found that some of the isoforms were similar in ways that they could be attached to their DNA – such as height and weightpersonality traits (such as nicotine addiction), and even educational status (suggesting that intelligence may be linked to genes).
“It is said that our face reflects our soul,” Esteller says. “Being less poetic, our amorphous person answered a large questionnaire to understand their physical and behavioral features. We noticed that those lookalikes with high concordance in facial algorithms and genetic similarities shared not only the face, but also other features….”
So, what explains those genetic similarities? It’s likely by chance and serendipity, Estiller says, driven by population growth, rather than the result of a previous or unknown association of ancestors or families. He explains that there are only so many things that make up a human’s facial features, so it stands to reason that some people – fortunately – would look like others.
“Given that the human population is now 7.9 billion, it is increasingly likely that these similar occurrences will occur,” he says. “A larger set analysis will provide more genetic variants shared by these particular haplo pairs, and could also be useful in clarifying the contribution of other layers of biological data to defining our faces.”
In addition to the study’s curious science attraction, Esteller believes his findings could help diagnose diseases using DNA analysis. They may help police hunt down criminals one day in the future – giving forensic scientists, for example, the ability to create sketches of suspects’ faces based on DNA samples found at crime scenes.
“There are two very exciting areas now for further development,” he says. First: Can we conclude from facial features that there are genetic mutations associated with a higher risk of developing a disease such as diabetes or Alzheimer’s? Second, can we now from the genome reconstruct a face that would be very useful in forensic medicine? Both search paths can now be continued.”
hear from Doppelgangers
for Marisa Munsing and Christina Lee, who co-authored the similar study, the social implications of Esteller’s research are just as important as the scientific findings.
Munzing, who has known Lee since they met in their freshman year at UCLA 14 years ago, had not expected to discover that their DNA was an exact match.
“I was definitely surprised by that [we] She might have similar DNA, like twins, with my friend,” she said in an email. “How crazy you are!! And cool! I call it “twin” from time to time so I guess it fits really well now! “
But, she says, knowing that we all may have a secret twin could help bring people together at a time when Americans and others around the world are deeply divided along class, social and political lines.
Lee agrees, noting that having a friend with a closely identical genetic profile “and even a similar face” adds to the sense of connection to others we might consider strangers.
“It can be good to feel like you’re not alone, even if it’s only in your appearance,” she says.
“We’re really more similar and connected to each other than we think,” Munzing says.