People who look extremely similar often also have similar genetic characteristics. This was the result of an analysis of doubles, photos of which had originally been collected for an art project. The genetic similarities also determine characteristics such as smoking behavior or the level of education in addition to the external features, report researchers from Spain in the specialist magazine “Cell Reports”. The results of such analyzes could therefore contribute to clarifying the question of whether genes or the environment shape people more.
The team led by Ricky Joshi from the Josep Carreras Leukemia Research Institute in Barcelona used photos that the Canadian artist Francois Brunelle has been collecting since 1999 of doubles worldwide. The researchers chose 32 of these pairs and first had the portraits objectively evaluated in terms of their similarity using three different software programs. 16 of the 32 pairs were classified as very similar by all three models.
For a genetic analysis, the researchers asked these selected doubles for a saliva sample. It turned out that the 16 couples were also similar in certain genetic characteristics. After the genome analysis, the scientists described nine of them as “ultra doppelgangers”. Many of the genetic similarities involved genes that help define appearance and facial features.
However, the scientists found no match when they looked at the so-called epigenome. This summarizes chemical changes in the genetic building blocks – they also differed significantly in the doppelganger pairs. The bacterial composition in the saliva also did not indicate an extraordinary agreement.
“Our study offers a rare insight into human similarity, showing that people with extremely similar faces share genotypes while mismatching at the epigenome and microbiome level,” explains lead author Manel Esteller. “The genomics brings them together, and the rest sets them apart.”