Humans diverged from chimpanzees and other great apesroughly 6m years ago.
But what exactly was it that enabled our brains to reach such mindboggling heights?
We know that the human brain has dramatically expanded in size over the past 6m years.
Humans are in fact the mammals with the largest brain relative to body size.
Now a new study,published in Nature, offers clues.
These stem cells can begenerated directlyfrom cells of adult origin, such as skin or blood cells.
They are then grown in a gel that allows them to develop three-dimensionally.
And thats exactly what the researchers behind the new study did.
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Genetics of evolution
So what kind of genetic changes do we think contributed to human brain evolution?
Only about 1.5 percent of our DNA actually consists of genes with instructions for making proteins.
Proteins are the molecules that do most of the work in cells and determine the cells structure and function.
It was once thought that the remaining 98.5 percent of DNA wasjunk with no clear purpose.
The vast majority of our genes are therefore identical.
The authors observed that human brain development occurs at a slower pace than the other two primates.
Gene expression doesnt tell the whole story though.
Its rate is ultimately controlled by a process calledgene regulation.
These accessible regions of DNA have the potential to interact with proteins and can regulate gene expression.
This study takes the first steps in pinpointing interesting candidate genetic regions responsible for human brain complexity.
It does, however, provide an excellent resource and starting point to direct future research in this direction.
Several studies have found that mutations in regions of DNA withhuman-specificchanges are associated withneurodevelopmental disorders.
