Researchers have found the reason behind the lack of tails in humans.

Scientists have been contemplating a question for many years: Why do humans not have a tail, despite the fact that our primate ancestors did?

Scientists have possibly uncovered the genetic process that is responsible for both our lack of tails and that of our ape ancestors.

This seems to be correlated with a genetic mutation in a crucial gene.

The disappearance of the tail in many vertebrates, which has been observed for more than 500 million years, may have given our ancestors an edge as they moved from living in trees to living on land, as concluded by scientists.

The scientists studied the genetic makeup of two sets of primates: one with tails, such as monkeys, and one without tails, including humans and apes. They discovered a genetic change in the TBXT gene that was present in apes and humans but not in monkeys. To investigate the impact of this mutation, the researchers altered the genetics of laboratory mice to express this characteristic. As a result, the mice either had shorter tails or no tail at all.

“We have presented a likely explanation for the genetic process that resulted in the disappearance of the tail in our predecessors. It is remarkable that a drastic physiological alteration could be attributed to a minor genetic mutation, as stated by Itai Yanai, a geneticist and systems biologist at New York University Langone Health and co-leader of the research published in the journal Nature.”

The absence of a tail may have improved the body’s balance for upright movement and eventual bipedalism. Bo Xia, a geneticist and systems biologist from Harvard University and the Broad Institute, stated this as the lead author of the study.

Around 25 million years ago, researchers believe that a genetic change resulted in the loss of tails among apes, when they emerged from primates. Our species, Homo sapiens, has been around for approximately 300,000 years.

The ancestral path that resulted in the development of apes and humans diverged from the path that gave rise to present-day Old World monkeys, such as baboons and macaques. Today’s hominoids consist of humans and both “great apes” (chimpanzees, bonobos, gorillas, and orangutans) and “lesser apes” (gibbons). The initial recorded hominoid, named Proconsul, lacked a tail.

The formation of fewer tail vertebrae occurred in hominoids, resulting in the loss of an external tail. However, vestiges of a tail can still be found in humans. The coccyx, also known as the tailbone, is a bone made up of fused remnants of the tail vertebrae, located at the base of the spinal column.

Many animals with backbones have used their tails for various purposes such as moving around and protecting themselves. For instance, fish and whales use their tails to move through water, while some dinosaurs had tails that they could use as weapons. Certain species of monkeys and other animals have the ability to grip onto objects, like tree branches, with their tails.

According to Yanai, having a tail may have benefits for those who live in trees. However, once they move onto land, it could become more of a disadvantage.

The advantages obtained by going tailless appear to have come with a cost. Because genes may contribute to multiple functions in the body, mutations that confer an advantage in one area may be detrimental in another.

The altered mice exhibited a slight rise in the presence of major abnormalities during childbirth, specifically neural tube defects in the spinal cord similar to spina bifida seen in humans.

According to Yanai, this indicates that the drive to lose the tail in the evolutionary process was strong enough to overcome the potential consequence of neural tube defects. As a result, the tail was ultimately lost.

It is thought-provoking to consider the possibility of humans evolving with tails.

Source: independent.co.uk