In our opinion, we could not have become modern humans if our ancestors had not lost this gene.

We humans are the products of evolution. About two or three million years ago, after the functional loss of a single gene, a number of major changes occurred in humans, which ultimately helped us to become a modern human species that we are today. It changed everything.

Recently, a group of researchers at the University of California San Diego School of Medicine published a new article in which it is written that humans could become one of the best long distance runners in animals . Kingdom. The document was published in Acts of the Royal Society BNumber of September 12th. According to the article, the researchers conducted experiments on mice designed to not have this same gene, called CMAH.

At about the same time that the predecessors of humans lost the CMAH gene, they were also starting to move from forests to dry African savannahs. Major skeletal biomechanics and physiological changes occurred in their bodies. He also led to long, bouncy legs, big feet, and strong buttocks. Another thing appeared in the bodies of these human ancestors who differentiated them from all other large mammals – a vast system of sweat glands, capable of hunting heat more efficiently. These types of changes have allowed human ancestors to travel long distances without comparing themselves to other mammals. Thus, they could hunt even during the day, when the temperature was higher, while other carnivores were resting.

"More than 20 years ago, we discovered this first obvious genetic difference between humans and our closest evolving relatives, chimpanzees," said lead author of the new article, Ajit Varki, MD, Distinguished Professor medicine and cellular and molecular medicine. at UC San Diego School of Medicine. He is also co-director of the UC San Diego / Salk Center for Academic Research and Training in Anthropology.

Varki began the investigation with a professor of anthropology and pathology, Pascal Gagneux, PhD. They were trying to discover how the genetic difference could have contributed to the origin of Homo, the genus that includes modern Homo sapiens as well as extinct species, such as Homo habilis and l 39; Homo erectus.

"Since mice were also more prone to muscular dystrophy, I thought that there was a connection to Homo's long run and endurance, but I had no expertise on the subject and I could not convince anyone of this long-term experience, "Varki said.

Finally, Jon Okerblom, a graduate student, built mouse casters and borrowed a mouse pad. "We evaluated exercise capacity (mice lacking the CMAH gene) and noted increased performance during treadmill tests and after 15 days of voluntary running," said the study's first author. .

The team then discussed the issue with Ellen Breen, Ph.D., who is a research scientist in the Division of Physiology, Department of Medicine, School of Medicine, University of San Diego. He observed that the mice were more resistant to fatigue. They also had increased mitochondrial respiration and lower extremity muscles, with more capillaries, which increased the intake of blood and oxygen in their bodies.

The data thus alluded to the fact that the loss of CAHM helped the mice to improve and improve skeletal muscle 's ability to use oxygen. "And if discoveries translate into humans, they may have given early hominids a selective advantage in their passage from trees to becoming permanent hunter-gatherers in the open," he added.

During the mutation of the CMAH gene in the bodies of human predecessors about two or three million years ago, they used sialic acids, a family of sugar molecules that covered all the walls of animal cells. At this point, they become essential points of contact for interaction between cells and the environment. The loss of this gene has caused the loss of a sialic acid, N-glycolylneuraminic acid (Neu5Gc), in hominids and modern humans. Instead, he built his precursor, called N-acetylneuraminic acid or Neu5Ac. The only difference between these two is a single atom of oxygen.

Although the difference seems to be minor, it actually affects almost all types of cells in the human body. This change has been a blessing and a curse for modern humans.

Researchers believe that the mutation of the CMAH gene and the loss of sialic acids are not only related to the improved ability of humans to travel long distances, but they have also increased innate immunity in early hominids. They also concluded that sialic acids could be a biomarker of cancer risk.

On the other hand, the article indicates that some sialic acids are linked to high risk of type 2 diabetes and can trigger inflammation. They can also contribute to the increased risk of cancer related to the consumption of red meat.

"They are a double-edged sword. The consequence of a single gene lost and a small molecular change that seems to have profoundly altered human biology and abilities goes back to our origins, "said Varki.