# Exploring the Genetics Behind Your Doppelganger
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Chapter 1: The Fascination with Look-Alikes
Have you ever greeted someone only to realize they weren't the person you thought? Or found yourself puzzled by a list of celebrity look-alikes, unsure who the original is? This phenomenon is so intriguing that there are even talent agencies dedicated to finding doppelgangers.
Despite the vast diversity among nearly 8 billion people worldwide, some seemingly unrelated individuals bear an uncanny resemblance to one another. This concept is not only popular in reality but also frequently explored in fiction, often portraying the 'evil twin' attempting to usurp the life of their 'good counterpart.'
While it’s easy to attribute resemblance among family members, particularly twins, to genetic factors, the question remains: do unrelated look-alikes share similar genetic traits? Although we can modify our appearance in various ways, our genetic makeup forms the underlying basis for our distinct facial features.
However, the answer to this question has remained elusive... until now.
Section 1.1: Unraveling the Genetic Connection
Recent research delves into the physical similarities and disparities among unrelated look-alikes. Researchers benefited from a project by Canadian photographer François Brunelle, titled "I’m Not a Look-Alike!", which featured 32 pairs of look-alikes (ages 21–78, including 21 female pairs) since its inception in 1999.
The researchers reached out to these participants, requesting biometric data, lifestyle questionnaires, and saliva samples. To confirm the visual likeness of the pairs, the scientists employed three different facial recognition algorithms. Remarkably, over 75% of the participants resembled each other almost as closely as identical twins according to two of the algorithms, while around 50% matched under all three.
This means that look-alikes genuinely do resemble one another.
Section 1.2: The Science Behind the Samples
Next, the researchers analyzed the saliva samples for three different types of data: genetic, epigenetic, and microbiome.
Genetics: The standout finding was that look-alikes shared over 19,000 SNPs (single-nucleotide polymorphisms) across more than 3,700 genes. Notably, nearly 1,800 of these genes are classified as 'face genes' linked to traits such as cleft lip/palate, eye color, hair loss, and other facial characteristics.
Epigenetics: Interestingly, only one pair of look-alikes showed a level of epigenetic similarity that surpassed what would be expected by chance.
Microbiome: Similarly, just one pair exhibited a closer match than anticipated. It's worth noting that this refers to the oral microbiome; we lack information on gut microbiota.
What about looking beyond physical features?
Chapter 2: Common Traits Beyond Appearance
The study revealed that look-alikes also exhibited similarities in height, weight, smoking habits, and educational attainment. In essence, physical traits such as body weight and height, along with behavioral traits like smoking and education, were correlated among the look-alike pairs. This suggests that shared genetic variations may not only influence physical appearance but also impact lifestyle choices and behaviors.
It's important to acknowledge the limitations of the study, including the small sample size, as genuine look-alikes are quite rare. Additionally, the majority of the pairs were of European descent, raising questions about how well the facial recognition algorithms would perform across diverse ethnicities—a continuing area of concern.
So, who’s your celebrity twin?
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