For many years, scientists have pondered why our species is devoid of a tail.
A team of scientists from New York and Harvard universities reported that this is related to a mutation of an important gene.
What researchers have learned
Thus, scientists have deciphered the genetic mechanism responsible for our taillessness.
According to scientists, tails were a defining feature of most vertebrates for over half a billion years. Their disappearance around 25 million years ago may have provided certain advantages to our ancestors as they transitioned from an arboreal environment to a terrestrial one. In other words, tails were important for moving through trees, but on land, the need for this function diminished.
In total, the development of tails in various vertebrate species was associated with more than 100 genes. The authors of the study suggested that humans lost their tails due to changes in one or more of these genes in the code. DNA .
Ultimately, the team discovered that the gene TBXT is responsible for tail loss in humans. It determines the length of the tail in some animals. When a small piece of DNA called AluY was inserted into it, tails were lost.
AluY fragments are also referred to as “jumping genes” or “mobile elements” because they can move and insert themselves into DNA code spontaneously and repeatedly. These elements are also responsible for regulating tissue genes and can alter the way they are expressed, the publication reported. Daily Mail .
What is the essence? research
During the study, scientists identified two jumping genes in the TBXT of primates. This led the team to hypothesize that AluY randomly inserted itself into the DNA code tens of millions of years ago.
To uncover the mystery, researchers introduced jumping genes into 63 mice and found that the tails of their offspring were either shorter or completely absent.
Moreover, the AluY insertion remained in the same location of the TBXT gene, which contributed to the formation of two RNA forms of TBXT. And one of these forms apparently caused the loss of the tail.
According to researchers, gorillas, chimpanzees, and early humans lost their tails when they diverged from Old World monkeys. After this evolutionary split in the group of primates that includes modern humans, there were fewer tail vertebrae formed, which led to the development of the coccyx.
The famous naturalist Charles Darwin discovered changes in the anatomy of our ancestors in his work “The Descent of Man and Selection in Relation to Sex” (1871). However, he was not convinced that the coccyx was an ancient tail.
“Our research explained how evolution removed our tails. This question has intrigued me since my youth,” said the lead author of the study, Bo Xia.
The results of the study were published in the journal Nature.