The Marathon Gene

Ultimately, a graduate student named Jon Okerblom took up the task, building mouse running wheels and borrowing a mouse treadmill. “We evaluated the exercise capacity (of mice lacking the CMAH gene), and noted an increased performance during treadmill testing and after 15 days of voluntary wheel running,” said Okerblom, the study’s first author. The researchers then consulted Ellen Breen, PhD, a research scientist in the division of physiology, part of the Department of Medicine in the UC San Diego School of Medicine, who added observations that the mice displayed greater resistance to fatigue, increased mitochondrial respiration and hind-limb muscle, with more capillaries to increase blood and oxygen supply. Taken together, Varki said the data suggest CMAH loss contributed to improved skeletal muscle capacity for oxygen utilization. “And if the findings translate to humans, they may have provided early hominids with a selective advantage in their move from trees to becoming permanent hunter-gatherers on the open range.” When the CMAH gene mutated in the genus Homo two to three million years ago, perhaps in response to evolutionary pressures caused by an ancient pathogen, it altered how subsequent hominids and modern humans used sialic acids — a family of sugar molecules that coat the surfaces of all animal cells, where they serve as vital contact points for interaction with other cells and with the surrounding environment. The human mutation causes loss of a sialic acid called N-glycolylneuraminic acid (Neu5Gc), and accumulation of its precursor, called N-acetylneuraminic acid or Neu5Ac, which differs by only a single oxygen atom. This seemingly minor difference affects almost every cell type in the human body — and has proved to be a mixed blessing. Varki and others have linked the loss of the CMAH gene and sialic acids to not just improved long-distance running ability, but also enhanced innate immunity in early hominids. Sialic acids may also be a biomarker for cancer risk. Conversely, they have also reported that certain sialic acids are associated with increased risk of type 2 diabetes; may contribute to elevated cancer risk associated with red meat consumption; and trigger inflammation. “They are a double-edged sword,” said Varki. “The consequence of a single lost gene and a small molecular change that appears to have profoundly altered human biology and abilities going back to our origins.” https://www.technologynetworks.com/genomics/news/researchers-claim-discovery-of-a-long-distance-running-gene-309435?utm_campaign=Newsletter_TN_BreakingScienceNews&utm_source=hs_email&utm_medium=email&utm_content=65858443&_hsenc=p2ANqtz-9jqOwssMElhLJJKvP_dYLOH7r3rX_EYUkb08xnQfp4KSaGcOG_29yyzKGrbkPsxWMjlecFpKky7yK91UbB_vVpg8dHtw&_hsmi=65858443