“Hu­mans can run for long dis­tances at a sus­tained pace”

Bi­ol­o­gists have iden­ti­fied a mu­tated gene that might ex­plain why hu­mans are so good at en­durance run­ning. Prof Ajit Varki of the Univer­sity of Cal­i­for­nia, San Diego, ex­plains

Focus-Science and Technology - - DISCOVERIES -

How do hu­mans com­pare against other an­i­mals?

Many an­i­mals are ca­pa­ble of short-dis­tance sprints, but few do en­durance run­ning, be­sides horses, wolves and os­triches. None of the other pri­mates run long dis­tances and hu­mans are very un­usual in that we can run for very long dis­tances at a sus­tained pace – if you’re in rea­son­able phys­i­cal con­di­tion.

When did our an­ces­tors gain run­ning abil­ity?

Based pri­mar­ily on the struc­ture of bones and likely im­plan­ta­tion of mus­cles, the fos­sil record says it prob­a­bly be­gan with Homo erec­tus, which even­tu­ally gave rise to our lin­eage. About 2 mil­lion years ago, the skele­ton changed dra­mat­i­cally: you got a struc­ture that’s much like mod­ern hu­mans - the strid­ing, bipedal gait of a healthy young per­son, which can break into a run.

Which genes in­flu­ence en­durance run­ning?

CMAH is the first known gene that might con­trib­ute to en­durance run­ning – it’s been around for 500 mil­lion years and got lost in our an­ces­tors. The gene pro­duces an enzyme that adds an ad­di­tional oxy­gen atom to mol­e­cules on the cell sur­face, called sialic acid. Through­out the body, sialic acid en­ables cells to in­ter­act with one an­other. We still have the same amount of to­tal sialic acid, but we lost one ma­jor form due to a mu­ta­tion in the CMAH gene about 2-3 mil­lion years ago – which co­in­cides with when our an­ces­tors gained the abil­ity to run long dis­tances.

You made mice with hu­man-like mu­tated genes. How did they run?

There were two tests. One was a stress test: we put nor­mal and mu­tant mice on tread­mills and they ran un­til they reached ex­haus­tion. The reg­u­lar mice ran for 25 min­utes, whereas the mice with hu­man-like CMAH genes ran for 35 min­utes. Im­por­tantly those mice had not even been trained, they had been couch pota­toes. Then we put run­ning wheels into the cages; mice love to run – they run kilo­me­tres at night. Ini­tially there was not much dif­fer­ence, but over 10-15 days, the ‘hu­man­ised’ mice got bet­ter. And when we took those trained mice and put them back on the tread­mill test, the dif­fer­ence was even more ob­vi­ous: the mu­tant mice ran for 60 min­utes in­stead of 40, so around 50 per cent longer. We col­lab­o­rated with Ellen Breen, who looked at their mus­cle bi­o­log­i­cally and showed it had

de­creased fa­tigue, im­proved oxy­gen util­i­sa­tion and some other fac­tors.

What does your study re­veal about hu­mans?

Of course, mice don’t have many other fea­tures that hu­mans have, such as our up­right pos­ture and abil­ity to sweat. But if we can un­der­stand the dif­fer­ence be­tween the two kinds of mice in more phys­i­o­log­i­cal-, molec­u­lar­level de­tail, that may be rel­e­vant to ath­letic train­ing. Evo­lu­tion gave hu­mans this ben­e­fit of be­ing able to do sus­tained ex­er­cise. It’s clearly part of our ge­netic her­itage. The irony is that this CMAH gene mu­ta­tion may have made us more prone to cer­tain dis­eases, such as di­a­betes and car­dio­vas­cu­lar dis­ease. But if you just did your ex­er­cise reg­u­larly, es­pe­cially en­durance ex­er­cise, you would ben­e­fit.

ABOVE: Kenya’s Eliud Kip­choge won Septem­ber’s Berlin Marathon in 2:01:39. The IAAF had yet to rat­ify his time as this is­sue went to press but if it does, Kip­choge will have knocked 1:18 off fel­low Kenyan Den­nis Kimetto’s world record (2:02:57) set in 2014

BE­LOW: Hu­mans are unique among pri­mates for our en­durance run­ning ca­pa­bil­ity, and sci­en­tists be­lieve they’ve iden­ti­fied the gene that ex­plains why

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.