The perennial mystery as to why the human brain is larger and more complex than that of other animals has been cleared by researchers.
The human brain, with its unequaled cognitive capacity, evolved rapidly and dramatically.
"We wanted to know why," says James Sikela, PhD, who headed the international research team that included researchers from the University of Colorado School of Medicine, Baylor College of Medicine and the National Institutes of Mental Health.
"The size and cognitive capacity of the human brain sets us apart. But how did that happen?"
"This research indicates that what drove the evolutionary expansion of the human brain may well be a specific unit within a protein - called a protein domain-that is far more numerous in humans than other species."
"The take home message was that brain size may be to a large degree a matter of protein domain dosage," Sikela says. "This discovery opens many new doors. It provides new tools to diagnose diseases related to brain size. And more broadly, it points to a new way to study the human brain and its dramatic increase in size and ability over what, in evolutionary terms, is a short amount of time."
The study was recently published in the online edition of The American Journal of Human Genetics.