One of the most remarkable changes in human evolution is the loss of our tails, a transformation that occurred around 25 million years ago. This pivotal shift not only altered the trajectory of our species but also marked a significant moment in the evolutionary history of primates. While scientists have long speculated on why humans lost their tails, the genetic cause has remained elusive—until now. A recent study published in Nature has finally uncovered the genetic factors responsible for this evolutionary change.
The Quest to Understand Tail Loss
The journey to unravel the mystery of human tail loss began in an unexpected way. Bo Xia, a graduate student at New York University, was inspired to investigate the origins of the human tailbone after injuring his own coccyx. This personal curiosity led Xia and his team to embark on a groundbreaking scientific investigation.
Through careful research, the team focused on the TBXT gene, which plays a crucial role in regulating tail length in various species. Their research revealed a unique genetic mutation within this gene, providing a major breakthrough in understanding human evolution.
The Role of Jumping Genes
A key aspect of this discovery lies in the role of Alu elements, often called “jumping genes.” These genetic elements, specific to primates, can move within the genome and cause significant changes. The researchers found that Alu elements inserted themselves into the TBXT gene, triggering a chain reaction that led to the loss of our tails.
This insertion activated a process known as alternative splicing, where RNA molecules are cut and restructured, which ultimately led to the deletion of a crucial exon. This change altered the structure and function of the resulting protein, leading to the tail loss seen in humans.
Validation Through Mice Studies
To confirm their findings, the researchers engineered laboratory mice with the same genetic mutations found in humans and apes. These genetically altered mice lost their tails, providing compelling evidence that the identified mutation plays a crucial role in the absence of tails in humans and other primates.
However, the study also uncovered a downside to tail loss: an increased risk of neural tube defects, such as spina bifida. This finding highlights the complex balance between evolutionary benefits and potential genetic trade-offs.
The Broader Implications
This discovery has profound implications not just for understanding human evolution, but also for human anatomy and health. The loss of our tails was not a random event but a genetic adaptation with lasting consequences. It illustrates the complex relationship between genetic changes and the way they shape our physiology over time.
As we continue to study our evolutionary past, these findings remind us of the intricate process of natural selection and genetic innovation that has shaped humanity. This breakthrough also underscores the power of scientific inquiry in uncovering the mysteries of our origins, offering insight into the past that can help us understand our future.
The identification of the genetic reasons behind tail loss is a testament to the persistence of scientific exploration and the ongoing quest for knowledge about our evolutionary journey.
Late Titanic star Bill Paxton revealed true feelings about his own fearful experience of submersible dive for movie
In 2003, years after the Titanic film was released to the public, actor Bill Paxton opened up about how he went on a submersible ride to experience everything firsthand as well.
The interview was ahead of the documentary Ghosts of the Abyss release. The documentary showed director James Cameron discussing his inspiration for the film and taking several people, which included Paxton, on unscripted dives to the Titanic’s site.
“Each dive, I had to kind of look myself in the mirror and go ‘OK, are you ready for this?’” Paxton said in the 2003 interview. “It’s one of those things where Jim [Cameron] asked me in passing to go and…the opportunity of a lifetime. I jumped at it,” the actor explained.
“But then you start thinking about physically what’s going to be required of you to get into a three-man, deep-sea Russian submersible for a 13-hour dive,” he shared. “To go down two and a half miles to a place where the sun has never penetrated. And you’re starting to think ‘OK, I’ve got young kids. I need to get them to an age where they can support themselves before I do something this crazy.’”
“Jim is an infectious guy. And also, God, who wouldn’t go on this adventure?”
He even went on to even talk about how comfortable the inside of the submersible he dived in was. He said it was “relatively comfortable,” before noting that “certainly there are things that can go wrong.”
“If they do go wrong, it’s not going to matter anyway. And it’s going to happen so quickly that you’re not even gonna know it happened, probably,” he noted. “These are the thoughts you have going in.”
He even explained how to him, “the price of admission” seemed “kind of low” given the “great experience” you got in return.
“You approach the bow, and then you rise up over it. And you’re looking down on the ship, and you are a ghost of the abyss. And the images stay with you. The images, they really have an effect,” he said before he talked about the “personal story” attached to the sunken ship.
Posted by R.I.P Bill Paxton on Sunday, June 13, 2021
“I think all of us at some time in our dreams or even our waking moments have pictured ourselves: What would it have been like to be on that deck? Knowing that the lifeboats had gone away. What were you gonna do? Contemplating your own fate. It’s this ultimate parable of, how would you measure up?” he questioned, calling the Titanic “a perfect tragedy.”
“You think about the people on the water. You think about the people on the boats looking back and seeing the stern of that ship come up out of the water like a city rising up out of the sea,” the actor said. “You think about the people in the water. I swam in the water out there, which was a very disconcerting experience because you think there’s that much ocean underneath you.”
It was clear that the actor knew of all the risks before going into the experience. As for the five men aboard the submersible that dominated headlines in the last week, the U.S. Coast Guard announced that they discovered “presumed human remains.”
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