Changes in the size and organization of the brain distinguish the emergence of modern humans, but we know little about the genetic basis of these changes. Researchers in the Netherlands have now combined large-scale neuroimaging and genomics data to identify genetic variants associated with anatomy and development of the human brain.
One feature that distinguishes the human brain from those of monkeys and apes is its size … Analyses of endocasts suggest that the cortical surface of Homo sapiens is dramatically expanded, and is shaped differently, compared to extinct hominin species.
These changes were likely accompanied by alterations in white matter tracts, the brain’s long-range connections. Together, they may have contributed to the emergence of language and other complex cognitive skills.
The findings, which are published in the Proceedings of the National Academy of Sciences, suggest that evolution of the human brain involved a gain of regulatory genetic elements in the genome. These “enhancers” become active in the fetal human brain and function to influence the activity of genes that contribute to the surface area of the cortex, one of these being ZIC4, which is implicated in neurogenesis, or the production of new brain cells.
