People who look alike may have similar DNA, study finds

People who look alike may have more in common than merely their comparable physical features – they might also share similar DNA, according to a new study.

Furthermore, lookalikes could even display similar common habits and behaviours, researchers have found.

Wading into the discussion over “nature vs nurture”, the study published on Tuesday in the journal Cell Reports saw scientists recruit “human doubles” photographed in the work of Canadian artist Francois Brunelle, who has been collecting pictures of globally-dispersed lookalikes since 1999.

The scientists began by asking 32 lookalike couples – scattered across 16 countries ranging from Chile, Angola, Belarus and Azerbaijan – to provide them with saliva DNA samples and complete biometric and lifestyle questionnaires, which quizzed them on activities such as eating, drinking smoking, and whether they had pets, children or romantic partners.

They then used three different facial recognition programmes to judge how determine how objectively alike each of the pairs were. Sixteen lookalike pairs were judged by all three programmes to share the same face.

In “striking” results, genetic analysis showed that nine of these 16 pairs shared similar genetic traits – compared with just one of the 16 pairs not matched by all three facial recognition softwares, according to the study, in which researchers also discounted the possibility of hidden family links.

Moreover, physical traits such as weight and height, as well as behavioural traits such as smoking and levels of education , were also more closely correlated in lookalike pairs.

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

“We provided a unique insight into the molecular characteristics that potentially influence the construction of the human face,” said senior author Manel Esteller, of the Josep Carreras Leukaemia Research Institute in Barcelona. “We suggest these same determinants correlate with both physical and behavioural attributes that constitute human beings.”

The researchers believe their findings could potentially help to further future efforts to solve crimes and improve medics’ ability to diagnose illnesses.

“These results will have future implications in forensic medicine – reconstructing the criminal’s face from DNA – and in genetic diagnosis – the photo of the patient’s face will already give you clues as to which genome he or she has,” said Dr Esteller.

“Through collaborative efforts, the ultimate challenge would be to predict the human face structure based on the individual’s multiomics landscape.”