Complex sentence: A unique feature of 8p is a big region of about 15 megabases that appears to have a high mutation rate, and which shows an immense divergence between human and chimpanzee, suggesting that its high mutation rates have contributed to the evolution of the human brain.
Split into simpler sentences: A unique feature of 8p is a region of about 15 megabases that appears to have a high mutation rate. This region shows an significant divergence between human and chimpanzee, suggesting that its high mutation rates have contributed to the evolution of the human brain.