We’ve all done a double take when we mistake a random person on the street for someone we know or know about, like celebrity lookalikes Will Ferrell and Chad Smith – the actor and Red Hot Chili Peppers drummer, respectively.
What are the chances of having a lookalike?
Does everyone have a lookalike? There’s actually a decent chance of this happening, thanks to the limited number of genes that influence facial features.
“There’s only so much genetic diversity out there,” Michael Sheehan, an assistant professor of neurobiology and behavior at Cornell University who routinely studies appearance variation and genetics in species like paper wasps and house mice. “If you shuffle that deck of cards that many times, at some point, you will be dealt the same hand twice.”
That said, that “deck of cards” is incredibly bulky, Sheehan noted. Scientists currently have no idea how many genes play a role in determining, for example, the shape of human faces or the space between people’s eyes.
There is a “huge number of genes that contribute to things like facial structure and, of course, hair color, eyes and skin, all of which are highly variable,” said Dr. Arthur Beaudet, a professor of molecular and human genetics at Baylor College in New York, of the lookalikes. Medicine in Houston.
Evolution appears to favor a large degree of distinctiveness in human races. Sheehan and a colleague reported last year in the journal Nature Communications that human faces differ in their size more than, for example, hands differ in their width and length. Furthermore, scientists have found that more genes are known to be linked to appearance than to other areas of human anatomy.
“Human faces are more variable than we would expect based on the variability of other body parts,” Sheehan said.
One plausible reason about lookalikes for the variety of faces is that humans, just like other social animals, benefit from the ability to distinguish individuals within their species. This way, those who act as benefactors or who act like jerks can be approached or avoided accordingly. “You care who is who,” Sheehan said.
Family members, of course, look much more alike on average than unrelated individuals, demonstrating that human faces are clearly hereditary. This is why so-called identical twins – who each developed from the same fertilized egg and therefore share all genes – are often difficult to distinguish. However, they are twins, not unknown lookalikes.
Therefore, it stands to reason that strangers who resemble each other enough to appear to be lookalikes — like Ferrell and Smith — are probably more closely related (but don’t know it) than people who look nothing alike, Beaudet said.
Furthermore, people of the same ethnicity typically have a broader set of genes in common than those outside their group, which is why, for example, South Asians usually have dark hair and brownish skin and Scandinavians of They usually have blond hair and pale skin.
“It’s not like you find an Asian and a European who look almost identical,” Beaudet said. “If you go back in time, you find two people of similar ancestry who probably, in fact, have a fair amount of genetic sharing.”
Although “ethnicity” is a complicated concept, involving non-genetic aspects such as culture and language, larger ethnicities or “races” – another term loaded with meaning – if considered as groups of people closely related genetically, should logically have greater chances of generating lookalikes.
The largest ethnic groups are the Han Chinese (about 1.3 billion people) and the Hindustani (possibly up to 1.2 billion people, from South Asia). If you are part of one of these groups, you are theoretically more likely to come across a lookalike.
This notion of people sharing genes and geography, and therefore appearances, is becoming blurred due to modern global migration. Individuals whose ethnic groups have been isolated for many millennia now regularly have children with each other.
“People weren’t moving much,” Beaudet said. “Today we have people mating with people from another continent.”
Over time, isolation from other human populations, together with exposure to specific environments – the cold of northern latitudes or the heat of equatorial ones, to give an overly simplified example – have led to the emergence, taking root and characterizing ethnic groups, new genetic mutations. Keep in mind that all humans began as Africans, millions of years ago.
Now, with once-isolated human groups pooling all their new genes, the lookalike effect could be both enhanced and diluted. After all, the world’s population has exploded from a mere one billion at the beginning of the 20th century to more than 7 billion today.
All those extra people around, even with confusing bloodlines, could increase the likelihood that people have an uncanny resemblance to the point of looking like lookalikes.
“If you have enough people,” Sheehan said, “you end up with someone who doesn’t look so crazy different.”
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