Evolution: Loss of the tail in the evolution of humans and apes Nature | Nature wallet

A research paper reports findings that provide evidence for the genetic basis of tail loss during hominin (humans and great apes) evolution.naturePublished this time, we modeled embryonic development using mice and found that when a “human-specific genetic factor” was inserted into a “gene associated with tail development,” a new isoform of the protein was created. Tail elongation. The results indicate that this genetic factor contributed to tail loss in humans and great apes. In addition, the authors suggest that humans and great apes may have lost their tails during evolution, making them more susceptible to neural tube defects.

Hominins (humans, chimpanzees, gorillas, orangutans, gibbons, etc.), unlike other primate species, do not have tails. The loss of the tail is one of the most notable physical changes that occurred in the evolutionary lineage that gave rise to humans and other great apes. However, the genetic mechanisms that promoted tail loss in hominin evolution remain unknown.

Now, Bo Xia, Jeff Buckey, and Itai Yanai and colleagues have examined 140 genes associated with vertebrate tail development to find changes that may have caused tail loss in humans, and the authors suggest that the insertion of a specific Alu sequence into a specific location in TBXT may be the gene (the gene involved in the development of Tail in animals tail) in the ancestor of hominins may have contributed to the loss of the tail. I have developed a hypothesis. To test this hypothesis, the researchers generated a mouse model that expresses both full-length and exon-deleted isoforms of the Tbxt gene (induced in hominins by introduction of Alu sequences). They found that mice expressing both isoforms of the Tbxt gene had no tails or short tails, depending on the ratio of expression in the embryonic tail bud. The researchers suggest that their results provide evidence that isoforms of the Tbxt gene with missing exons contribute to tail loss. They also found that mice expressing an isoform of the Tbxt gene with missing exons can develop neural tube defects. In humans, about 1 in 1,000 newborns develop a neural tube defect.

The authors suggest that the evolutionary loss of the tail may have had an adaptive cost: the potential for neural tube defects, which still affect human health today. An example of a neural tube defect is spina bifida, in which the vertebrae do not form properly in the mother's womb.

doi:10.1038/s41586-024-07095-8

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