Scientists Discover Some Keys to Human Brain Evolution

The questions surrounding why and how the human brain has evolved over the past six million years as compared to other primates in the evolutionary timeline have been central in the discussions of human origins research for many years. When and how did this happen? Some possible clues may have emerged as a result of new research by an international team of scientists in China and Germany, suggesting that changes in the activity levels of certain genes of the human brain during brain development may have been the cause, and that these changes were controlled by key regulatory molecules called microRNAs.


As reported in the open-access journal PLoS Biology, the researchers analyzed brain genetic activity in humans, chimpanzees and macaques across their lifetimes, beginning with newborns. They targeted two key brain regions: the cerebellum, which controls movement, and the prefrontal cortex, which plays a major role in cognitive behavior, such as abstract thought, innovation and social interaction. What they found was that the human gene activity displayed a markedly different pattern during individual life-time human brain development from that of chimpanzee and macaque primate counterparts. Moreover, the distinquishing patterns were most pronounced in the prefrontal cortex, where, for example, genes showing the human-specific changes were four times as numerous as those showing the chimpanzee-specific changes. Many of the genes showing the human-specific patterns were identified as having neural functions, suggesting a connection to cognitive development.


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