Discovery of a genetic link between the brain and the shape of the face
In a genome-wide association study involving 19,644 individuals of European descent, an international team of researchers identified 472 genomic regions, or loci, that influence brain shape, 76 of which are also linked to brain shape. of the face ; these loci do not influence cognitive abilities, further debunking beliefs that intelligence can be assessed by facial features.
âTo study the genetic basis of brain shape, we applied a methodology that we already had used in the past to identify the genes that determine the shape of our face, âsaid Professor Peter Claes, researcher at the Genetic Imaging Laboratory at KU Leuven.
âIn these previous studies, we analyzed 3D images of faces and linked several data points on those faces to genetic information to find correlations. “
âIn this way, we were able to identify various genes that shape our face. “
In the present study, the scientists used information stored in the British Biobank to study the brain structure – obtained by magnetic resonance imaging (MRI) – of 19,644 healthy people.
“In order to be able to analyze the MRIs, we had to measure the brains shown on the scans,” said Prof Claes.
“Our specific focus was variations in the folded outer surface of the brain – the typical ‘nut shape’.”
âWe then established a link between the image analysis data and the available genetic information. “
The authors found 472 loci in the genome that affect the shape of the brain. Of these, 76 have been previously shown to influence facial structure.
âIn this way, we identified 472 genomic regions that impact the shape of our brain. 351 of these locations have never been reported before, âhe said.
âTo our surprise, we found that up to 76 genomic locations predictive of brain shape had previously been linked to facial shape. This makes the genetic link between the face and the shape of the brain compelling. “
They also found evidence that genetic signals that influence both brain and facial shape are enriched in regions of the genome that regulate gene activity during embryogenesis, either in facial progenitor cells or in the developing brain.
“It makes sense because the development of the brain and the face are coordinated,” said Professor Joanna Wysocka, a researcher at Stanford University School of Medicine.
“But we didn’t expect this developmental crosstalk to be so genetically complex and to have such a broad impact on human variation.”
In the study, the team also briefly touched on conditions such as Alzheimer’s disease, schizophrenia, and bipolar disorder.
âAs a starting point, we used results previously published by other teams on the genetic basis of these neuropsychiatric disorders,â said Prof Claes.
“The possible link with the genes that determine the shape of our face has never been examined before.”
âIf you compare the existing findings with our new ones, you see a relatively large overlap between the genetic variants that contribute to specific neuropsychiatric disorders and those that play a role in the shape of our brain, but not for those that contribute to our face. . “
âIn other words: our risk of developing a neuropsychiatric disorder is not written on our face either.
“We were amazed to find 76 genetic regions that affect both facial and brain shape in the human population,” added Professor Wysocka.
âIt’s an incredible degree of overlap, and it shows how much these two structures influence each other during development. However, nothing in our data suggests that it is possible to predict behavior, cognitive function, or neuropsychiatric disorders like schizophrenia or ADHD just by looking at a person’s face.
The results appear in the newspaper Genetics of nature.
S. Naqvi et al. Shared inheritance of the human face and brain shape. Nat Genet, published online 5 April 2021; doi: 10.1038 / s41588-021-00827-w