Chimps \'r\' not us: an endurance gene for running (Introduction)

by David Turell , Thursday, September 20, 2018, 21:46 (2257 days ago) @ David Turell

We have a gene unlike a chimp gene, about three million years old, that gives our muscles the ability to run long distances and wear down animals so they stop and we kill them:

http://www.sciencemag.org/news/2018/09/broken-gene-may-have-turned-our-ancestors-marath...

"Despite our couch potato lifestyles, long-distance running is in our genes. A new study in mice pinpoints how a stretch of DNA likely turned our ancestors into marathoners, giving us the endurance to conquer territory, evade predators, and eventually dominate the planet.

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"Human ancestors first distinguished themselves from other primates by their unusual way of hunting prey. Instead of depending on a quick spurt of energy—like a cheetah—they simply outlasted antelopes and other escaping animals, chasing them until they were too exhausted to keep running. This ability would have become especially useful as the climate changed 3 million years ago, and forested areas of Africa dried up and became savannas. Lieberman and others have identified skeletal changes that helped make such long-distance running possible, like longer legs. Others have also proposed that our ancestors’ loss of fur and expansion of sweat glands helped keep these runners cool.

"Some clues came 20 years ago, when Ajit Varki, a physician-scientist at the University of California, San Diego (UCSD), and colleagues unearthed one of the first genetic differences between humans and chimps: a gene called CMP-Neu5Ac Hydroxylase (CMAH). Other primates have this gene, which helps build a sugar molecule called sialic acid that sits on cell surfaces. But humans have a broken version of CMAH, so they don’t make this sugar, the team reported. Since then, Varki has implicated sialic acid in inflammation and resistance to malaria.

"In the new study, Varki’s team explored whether CMAH has any impact on muscles and running ability, in part because mice bred with a muscular dystrophy–like syndrome get worse when they don’t have this gene. UCSD graduate student Jonathan Okerblom put mice with a normal and broken version of CMAH (akin to the human version) on small treadmills. UCSD physiologist Ellen Breen closely examined their leg muscles before and after running different distances, some after 2 weeks and some after 1 month.

"After training, the mice with the human version of the CMAH gene ran 12% faster and 20% longer than the other mice, the team reports today in the Proceedings of the Royal Society B. “Nike would pay a lot of money” for that kind of increase in performance in their sponsored athletes, Lieberman says.

"The team discovered that the “humanized” mice had more tiny blood vessels branching into their leg muscles, and—even when isolated in a dish—the muscles kept contracting much longer than those from the other mice. The humanlike mouse muscles used oxygen more efficiently as well. But the researchers still have no idea how the sugar molecule affects endurance, as it serves many functions in a cell.

"Similar improvements probably benefitted our human ancestors, says Andrew Best, a biological anthropology graduate student at the University of Massachusetts (UMass) in Amherst, who was not involved with the work. Varki’s team calculated that this genetic change happened 2 million to 3 million years ago, based on the genetic differences among primates and other animals."

Comment: This is a perfect example of how God might have stepped in and dabbled to improve human evolution and survival. Just one gene is altered. The work is in mice, but more than likely translates to humans.