As described at Eurekalert:
SAN FRANCISCO, CA—January 13, 2023—Humans and chimpanzees differ in only one percent of their DNA. Human accelerated regions (HARs) are parts of the genome with an unexpected amount of these differences. HARs were stable in mammals for millennia but quickly changed in early humans. Scientists have long wondered why these bits of DNA changed so much, and how the variations set humans apart from other primates.
Now, researchers at Gladstone Institutes have analyzed thousands of human and chimpanzee HARs and discovered that many of the changes that accumulated during human evolution had opposing effects from each other.
If humans and chimps differ in only 1% of our DNA, obviously, DNA is not the best place to look for the differences.
The findings, she says, have implications for understanding human evolution. In addition—because she and her team discovered that many HARs play roles in brain development—the study suggests that variations in human HARs could predispose people to psychiatric disease.
Among life forms, psychiatric disease is, pardon us, a high-class worry.
It’s a serious problem, to be sure. But to have it, you have to have a mind. Which sets you apart from trillions of life forms right away. Including chimpanzees. The paper is open access.