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from the insert-something-witty-about-Logan-here dept.
This broken gene may have turned our ancestors into marathoners—and helped humans conquer the world
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. [...] 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 [DOI: 10.1126/science.281.5382.1432] [DX]: 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 [DOI: 10.1126/science.322.5902.659] [DX] and resistance to malaria [DOI: 10.1126/science.329.5999.1586] [DX].
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 [DOI: 10.1098/rspb.2018.1656] [DX], 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.
Also at Discover Magazine.
(Score: 0) by Anonymous Coward on Sunday September 16 2018, @12:29PM (1 child)
We have to remember that the water issue would also be problematic for the prey and that they can't carry pig bladders with them full of lovely thirst quenching water.
Also apparently the oldest known spears are only about 350,000 years old.
I'm not convinced they did but I'm not convinced neither that they did not. It's certainly a fact that the modern ultra runners are amazing athletes running non-stop for very long times in very hard terrains and climates.
(Score: 0) by Anonymous Coward on Sunday September 16 2018, @04:10PM
The prey generally don't sweat as much and don't need as much water. Water is probably a problem BUT the prey still do manage to run for hours based on popular persistence hunting time ranges (wiki says 2-5 hours).
I'm pretty sure persistence hunting is possible but it's more risky and more time and resource intensive so I doubt it is something the most of those hominids would have done on a regular basis if they were as smart as a chimpanzee or smarter. Maybe it's what a hominid would do if it's alone and wants meat and can't catch it in other ways.
Maybe the ones with spear heads and the thrown ones but a long sharpened stick will still kill an antelope in an ambush. Even chimps use sharp sticks to kill stuff: https://www.iflscience.com/plants-and-animals/innovative-female-chimps-may-have-pioneered-tool-use-hunting/ [iflscience.com]
So I'm pretty sure stabbing spears will have been around for way longer. And definitely way before they used pig bladder waterskins.
A bipedal hominid advantage is we have arms to more easily carry lots of meat home and not have to eat it and carry it in our stomachs. Nor do we need to have our young nearby so we can easily drag the carcass to them (but also putting them at risk).
So the endurance running may be more for multiple ambushes. Run many times to chase animals to ambushes and you get a large pile of meat. Stop when you get too thirsty. Walk home with meat or jog home if it's too close to sunset. Whole family/village gets to eat lots of meat = big win.