The human brain is still a work in progress, according to scientists who have identified two rather new variants of genes that help to govern the organ’s size. A version of one gene, ASPM, emerged on the evolutionary scene only 6,000 years ago. The other, microcephalin, arose 37,000 years ago. Howard Hughes Medical Institute investigator Bruce T. Lahn (left) and his colleagues at the University of Chicago, who unearthed the genes, say they provide evidence that the brain is continually adapting and that there is no telling what it might look like in the far future. “We tend to think that we have reached the pinnacle of evolution,” Lahn says. But these findings show that “the human brain is still changing—and rather rapidly.”