More than 3000 regions in the human genome are very different to those in the genome of any other mammals, including our closest primate relatives.
A new study has evidence that nearly half of these so-called human accelerated regions (HARs) have played an important role in rewriting the course of human brain development.
To systematically identify which of the 3171 previously identified HARs are most likely to be contributing to recent evolution of the human cerebral cortex, the researchers examined the role of these regions in regulating genes in studies of multiple human and mouse cell types and tissues.
A new method they developed leveraged barcoded molecular inversion probes to capture target sequences that capture entire HAR elements and their surrounding DNA, overcoming some limitations of prior techniques. Using
this approach, they looked for important differences in HAR enhancer function between humans and chimpanzees.
Overall, the new findings show that many HARs do appear to act as neurodevelopmental enhancers, the researchers report.
The new data suggest that, as those human sequences diverged from other mammals, they have largely increased their role as neuronal enhancers.
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