PRESS-ASSOCIATION -- Humans may be defined by newly evolved "young" genes in the brain, a study has shown.
The research suggests genes that have only surfaced since the appearance of primates are what make humans special.
Previously, many scientists suspected it was the altered regulation of "old" conserved genes found in many species that produced the radically different human brain.
Researchers compared gene data from humans and mice and found that a higher percentage of primate-specific young genes were active in the brain.
The genes were also more likely to be active in recently expanded brain structures, such as the neocortex and prefrontal cortex. These are the brain regions responsible for "higher" levels of thinking.
"There is a correlation between the new gene origination and the evolution of the brain," said study leader Professor Manyuan Long, from the University of Chicago. "We're not talking about one or two genes, we're talking about many genes. This is a process that is continually moving and changing our brain."
The findings appear in the online journal Public Library of Science Biology.
The research showed that out of around 1,300 new genes, only 13% were involved in regulation. The rest were "new genes that bring a whole new type of function" said Prof Long.
They mostly became active during foetal or infant development.
Co-author Dr Maria Vibranovski, also from the University of Chicago, said: "This work will open a window such that people will start working in these new genes to try to figure out what exactly the functions are."