Mutations in a single gene decide the shape and size of the human cerebral cortex, influencing the creative and ingenious output that mankind has been capable of, claim researchers.
A team of researchers led by the Yale School of Medicine and three other universities conducted a genetic analysis on one Turkish family and two Pakistani families with offspring born with the most severe form of microcephaly.
The findings suggest that the children, whose brains were just 10 percent of a normal size, lacked the normal cortical architecture of the human brain.
This combination of factors has not been seen in other genes associated with the development of the human brain.
The researchers have found that mutations in the same gene, centrosomal NDE1, which is involved in cell division, were responsible for the deformity.
"The degree of reduction in the size of the cerebral cortex and the effects on brain morphology suggest this gene plays a key role in the evolution of the human brain," Murat Gunel, co-senior author of the paper and the Nixdorff-German professor of Neurosurgery and professor of genetics and neurobiology at Yale said.
"These findings demonstrate how single molecules have influenced the expansion of the human cerebral cortex in the last five million years. We are now a little closer to understanding just how this miracle happens," he added.
The findings have been reported in the current issue of the American Journal of Human Genetics.