Boston, MA – Scientists have recently discovered a genetic sequence responsible for the loss of tails in humans and great apes. This finding sheds light on a long-standing mystery regarding the absence of tails in these species. Tails, which are common among most animals with backbones, serve various purposes like balance, communication, and defense. However, humans and great apes diverged from Old World monkeys about 25 million years ago, leading to the loss of their tails.
Researchers identified an Alu element in the regulatory code of a gene linked to tail length, known as TBXT. This genetic sequence was previously dismissed as junk DNA but is now recognized as a crucial factor in primate taillessness. By studying genetic modifications in mice, scientists demonstrated how the Alu insertion in the TBXT gene affected tail lengths, further supporting their findings.
The study’s lead author, Bo Xia, emphasized the significance of this discovery, noting that it is the first time a genetic mechanism has been proposed to explain the loss of tails in humans and great apes. Furthermore, the findings have implications for understanding malformations of the neural tube during human fetal development, highlighting the broader impact of this genetic discovery.
Despite the new insights provided by this research, the question of why tails were lost in humans and great apes remains unanswered. Biological anthropologist Liza Shapiro suggests that the mutation responsible for tail loss may have been functionally beneficial or simply not a hindrance. Additionally, the evolution of bipedalism in humans may not have been directly linked to the loss of tails, as previously believed.
This study’s findings challenge long-standing assumptions about the role of so-called “junk” DNA in genetic evolution. The researchers’ use of CRISPR gene-editing technology to manipulate tail length in mice offers a glimpse into the complexities of genetic mechanisms underlying physical traits. The implications of this research extend beyond the realm of taillessness, potentially offering insights into human embryonic development and neurological defects.
The researchers’ investigation into the genetic factors contributing to tail loss highlights the complexity of evolutionary changes and the lasting impacts of genetic mutations. By uncovering the genetic sequence responsible for taillessness, scientists have opened new avenues for studying the development and evolution of species. This groundbreaking research underscores the intricate interplay between genetic elements and physical traits in the evolutionary history of humans and great apes.