Human accelerated regions
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Human accelerated regions (HARs), first described in August 2006, are a set of 49 segments of the human genome which are conserved throughout vertebrate evolution but are strikingly different in humans. They are named HAR1 through HAR49 according to their degree of difference between humans and chimpanzees (HAR1 showing the largest degree of human-chimpanzee differences of the 49). Found by scanning through giant genomic databases of multiple species, some of these highly mutated areas are thought to be responsible for development of human brain size, language, and complex thought.
Several of the HARs encompass genes known to produce proteins important in neurodevelopment. HAR1 is an 118 base pair stretch found on the long arm of chromosome 20 overlapping with part of the RNA genes HAR1F and HAR1R. It is found (and conserved) in chickens and chimpanzees but is not present in fish or frogs that have been studied. There are 18 base pair mutations different between humans and chimpanzees, far more than expected by its history of conservation.[1]
[edit] Sources and notes
- ^ Pollard K. et. al. An RNA gene expressed during cortical development evolved rapidly in humans. Advanced electronic publishing. Nature. August 16, 2006.
[edit] Further reading
- Scientific American article Scientists Identify Gene Difference Between Humans and Chimps published August 17, 2006
