Brain's wrinkled layer reveals genetic heritage

The three-dimensional shape of the cerebral cortex - the wrinkled outer layer of the brain controlling many functions of thinking and sensation - strongly correlates with one's ancestral background, says a study. The study opens the door to more precise studies of brain anatomy going forward and could eventually lead to more personalised medicine approaches for diagnosing and treating brain diseases.

"If we can account for a large percentage of brain structure based on an individual's genes, we are in a better position to detect smaller variations in the brain that might be important in understanding disease or developmental issues," said study's senior author Anders Dale from University of California, San Diego.

In their study, published in Current Biology, the researchers found they could predict with "a relatively high degree of accuracy an individual's genetic ancestry based on the geometry of their cerebral cortex". They found no relationship between brain shape and functional or cognitive abilities, Dale said, but rather a trove of information about how minute differences in brain geometry could be correlated with genetic lineage.

"The geometry of the brain's cortical surface contains rich information about ancestry," said study's first author Chun Chieh Fan. "Even in the modern contemporary US population, with its melting pot of different cultures, it was still possible to correlate brain cortex structure to ancestral background," Fan said.

There were various systematic differences, particularly in the folding and gyrification patterns of the cortex, the study said. The cortical patterns accounted for 47 to 66 percent of the variation among individuals in their genetic ancestry, depending on the ancestral lineage.