Human accelerated regions

Found by scanning through genomic databases of multiple species, some of these highly mutated areas may contribute to human-specific traits.

Others may represent loss of functional mutations, possibly due to the action of biased gene conversion[2][3] rather than adaptive evolution.

HAR1 is a 106-base pair stretch found on the long arm of chromosome 20 overlapping with part of the RNA genes HAR1F and HAR1R.

The HAR1 sequence is found (and conserved) in chickens and chimpanzees but is not present in fish or frogs that have been studied.

[7] The substitutions in HAR2 may have resulted in loss of binding sites for a repressor, possibly due to biased gene conversion.

Characterisation of HAR1-HAR5 regions, from a paper on Forces shaping the fastest evolving regions in the human genome by Katherine Pollard et al . [ 2 ]