How people lost their tails and monkeys held it

For the first time, American scientists believe that they have identified the critical mutation that disappeared the queues of our ancestors about 20 million years ago, while monkeys held it.

For about half a billion years, animals that were human ancestors had tails. The earliest fish used tails to swim in prehistoric seas, and much later, when primates evolved, their tails helped balance them as they moved from branch to branch in the trees. The earliest known primates 66 million years ago had regular tails and to this day many primates (including almost all monkeys) have retained them, as have many other mammals (eg rodents).

When apes appeared about 20 million years ago, they did not have a tail at all, as did the humans who evolved. At some point, 20 to 25 million years ago, it is estimated that the tails disappeared and Darwin was the first to point out this significant anatomical change according to the APE-MPE.

The mystery and the “guilty” mutation in DNA

How and why this happened remained a mystery. Now, American scientists claim to have found the “guilty” mutation in DNA. They believe that they confirmed it, because when they caused this gene mutation in mice, they did not develop normal tails. Other scientists have pointed out that it is impossible to prove with certainty that this mutation actually disappeared the tails, but it is very possible.

The researchers, led by Bo Xia of New York University School of Medicine, published the bioRxiv (which has not yet been published in a scientific journal), according to Science and the New York Times. They identified a mutation in the TBXT gene that is common in monkeys and humans but is absent in monkeys.

According to their theory, the mutation occurred suddenly in an ape 20-25 million years ago, causing it to cease to have a tail or to have only a very small one. Then, his queued offspring survived the game of natural selection, passing the mutation on to their offspring and so on. Eventually, the mutation in TBXT became common to all monkeys and humans. Scientists believe that this mutation is not the only reason people are born with a coccyx instead of a tail, as other genes involved underwent mutations later.

On the other hand, as other biologists point out, it is difficult to explain evolutionarily how tailless monkeys now have an evolutionary advantage, as they would fall much more often from trees due to poorer balance. Worse still, the mutation that wiped out the tails also increased the risk of birth defects in the spine, which now affect about one in 1,000 newborns.