In the epic of human evolution, a fascinating mystery has puzzled scientists: Why did we lose our tail? In the long history of human evolution, about 20 million to 25 million years ago, when apes separated from monkeys, the shedding of tails on the branches of our tree of life became a key node. Since Darwin's time, scientists have been working hard to solve this mystery.
New research has found that this mystery may have reached a breakthrough. In a study published in the journal Nature, geneticists at the Broad Institute, Xia Bo and his team noted that they found a key mutation in an important gene that may be one of the reasons for the disappearance of the tail.
To make this change, the researchers compared the genomes of six species of apes, including humans, and 15 species of monkeys with tails to reveal key differences between the two groups. Once a significant mutation was discovered, they used the gene-editing tool CRISPR to adjust the same gene locus in mouse embryos, resulting in mice that were born without tails.
However, researcher Xia warns that the disappearance of the tail may also be influenced by other genetic changes.
This discovery raises another mystery: did the loss of the tail really help the ape ancestors and ultimately the survival of humans, or was it just an accidental mutation in a thriving population?
Miriam Conkel, an evolutionary geneticist at Clemson University, said: "It may be random, but it may have created a huge evolutionary advantage. ”
As to why the loss of a tail may have contributed to evolution, there are several theories that are fascinating, some of which link taillessness to the eventual learning of humans to walk upright. Rick Potts, head of the Smithsonian Institution's Human Origins Project, noted that taillessness may be the first step for some apes to adopt a vertical body posture, even before they leave the woods.
Although today, not all apes live on the ground, orangutans and gibbons are still tree-dwelling tailed apes. However, scientists emphasize that they move in a very different way than monkeys with tails. The study's co-author, New York University biologist Itai Yanai, said that the loss of the tail was clearly a major evolutionary change, but that the only way to determine the cause "was to invent a time machine." This age-old mystery may be a small step forward, but the absolute answer to why we lost our tails is yet to be revealed by future scientific discoveries.