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At Sci News: Look-Alike Humans Have Similar DNA


New research led by Josep Carreras Leukaemia Research Institute scientists shows that people with extreme look-alike faces share common genotypes, but differ in their DNA methylation and microbiome landscapes.

“For decades, the existence of individuals who resemble each other without having any family ties has been described as a proven fact, but only in anecdotal terms and without any scientific justification,” said senior author Dr. Manel Esteller, a researcher at the Josep Carreras Leukaemia Research Institute.

“The widespread use of the Internet and social networks for image-sharing has meant that we are now able to identify and study such people.”

Look-alike humans share similar genotypes and differ in their DNA methylation and microbiome landscape. Image credit: Joshi et al., doi: 10.1016/j.celrep.2022.111257.

In their study, Dr. Esteller and his colleagues set out to characterize a set of look-alike humans on a molecular level.

To do so, they recruited human doubles from the photographic work of François Brunelle, a Canadian artist who has been obtaining worldwide pictures of look-alikes since 1999. They obtained headshot pictures of 32 look-alike pairs.

They determined an objective measure of likeness for the pairs using three different facial recognition algorithms.

In addition, the participants completed a comprehensive biometric and lifestyle questionnaire and provided saliva DNA for multiomics analysis.

“This unique set of samples has allowed us to study how genomics, epigenomics, and microbiomics can contribute to human resemblance,” Dr. Esteller said.

Overall, the results revealed that these individuals share similar genotypes, but differ in their DNA methylation and microbiome landscapes.

Half of the look-alike pairs were clustered together by all three algorithms.

Genetic analysis revealed that 9 of these 16 pairs clustered together, based on 19,277 common single-nucleotide polymorphisms.

Moreover, physical traits such as weight and height, as well as behavioral traits such as smoking and education, were correlated in look-alike pairs.

Taken together, the results suggest that shared genetic variation not only relates to similar physical appearance, but may also influence common habits and behavior.

“Our findings provide a molecular basis for future applications in fields such as biomedicine, evolution, and forensics,” Dr. Esteller said.

“Our study shows genetic markers that are critical in the development of the shape of the nose, lip, and mouth, plus completely novel determinants of bone structure and skin texture that also provide characteristic features of our face.”

“The environmental markers, such as the epigenome and the microbiome were more distinct between look-alikes and thus the differences in these people who resemble each other can be attributed to the chemicals that regulate the same DNA sequence and to the composition of the microbiome.”

“Because the human population is now 7.9 billions, these look-alike repetitions are increasingly likely to occur,” he said.

The findings appear today in the journal Cell Reports.

Complete article at Sci News.

It seems that nature has been producing “deep fakes” long before human technology developed that ability.

There may be some unintended biases in this approach. If two people who look alike were selected by searching through internet pictures, then they would have similar hair, and other non-genetic traits (glasses, beards, expressions) and be about the same age, as well as similar background (race, culture, social media). As such, they may be more predisposed to behave similarly, regardless of whether they look alike. I suppose I could read the actual article to see if they had any control samples: couples that share these traits without looking alike ... It is no surprise that the look-alike couples' microbiomes would differ since that depends more on family, environment and diet rather than genetics.Fasteddious
August 26, 2022
06:36 AM

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