It turns out that people who look nearly identical to someone we know share more than just those appearances with the person we know. A new study has found that these incredibly similar individuals share many genetic variants. More importantly, these variants affect not only their appearance but also the general characteristics of their lives. At the same time, other important influences, such as the microbiome in their bodies, don’t seem to contribute much to this symmetry.
Geneticist Manel Esteller, author of the study and director of the Josep Carreras Leukemia Research Institute (IJC) in Barcelona, Spain, says he is very interested in what influences the way people are. In 2005, he and his colleagues published research showing that identical twins are not as similar as they seem, but that although they do have some genetic patterns, there are changes in the epigenetic field, the way our genes manifest, mostly due to environmental or behavioral factors.
In their new research published yesterday in Cell Reports, Esteller’s team wanted to look the other way this time. So he scrutinized photos of people using three different face-recognition algorithms to find people who mostly looked alike but weren’t twins or even knew each other. Of the original 32 couples, 16 were perceived as the same by all three programs, and the researchers focused most of their work on this group.
These duos shared many of the most common genetic variations in humans, commonly referred to as single nucleotide polymorphisms (SNPs). Nine of the 16 pairs were so genetically matched that they were interpreted as “ultra” similarities. However, the epigenetics and oral microbiomes of these duos had relatively little in common.
Esteller told Gizmoda that these similar people are almost like real twins, their genetic sequences are very similar, but their epigenetic and microorganism flora profiles make the distinction. In addition, the genetic similarity between these couples did not end with their facial appearance. They were also more likely to have similar education levels, heights, weights, and even smoking histories than dissimilar pairs.
The researchers also went to great lengths to prove that these peers were not uninformed relatives. Although the couples often came from the same country or self-identified ethnicity, they were no more related than any two randomly selected individuals from the same community. Only one couple had a potential common ancestor in the past few centuries, while some couples lived on completely different continents. That’s why Esteller says they think some of these couples’ genetic similarities are due to random chance: “There are so many people on the planet that the system repeats itself – the genome combinations are no longer infinite.”
Esteller and her team’s research may shed light on the long-standing (or even centuries, or millennial) question of “innate or upbringing.” Although our genes appear to have an impact on our faces and other features that define who we are, both this research and Esteller’s earlier work show that not everything is entirely down to genetics.
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