Biologists from NYU Langone Health medical and research center in the US discovered that a mutation in the TBXT gene led to tail loss in human ancestors 25 million years ago. Research results published In the journal Nature.
The TBXT gene is responsible for tail length in animals with a tail. During the research, biologists discovered two “jumping” genes in TBXT, which are sections of DNA that were accidentally introduced into the human genome during the process of evolution. Jumping genes are DNA sequences that can change their position in the genome, sometimes creating or reversing mutations and altering a cell’s genetic identity and genome size.
In particular, according to scientists, human ancestors lost their tails due to the coincidental addition of a small region called AluY to the DNA. This piece is present in monkeys and humans, but not in monkeys of other species. To test this hypothesis, the researchers activated skipping genes in the genomes of laboratory mice. As a result of such an experiment, the tail length of the test subjects’ offspring was shortened (or absent).
Typically, most human introns (a type of transposable genomic element) carry repetitive, jumping copies of DNA without any effect on gene expression, the scientists noted.
Russian doctors before deleted a woman has a “tail” that extends from the uterus to the hips and rectum.