Cloning was once considered a way to imitate life perfectly, with the same results every time. But a long-term experiment on mice revealed a different truth.
The scientists followed the artificially created animals through several generations, and found that although the first clones appeared to be healthy, problems gradually increased.
Over time, the survival rate dropped, and in the 58th generation, cloning failed completely. The cause was not visible – it was hidden by accumulating DNA mutations.
A new study from Yamanash University shows that cloning cannot replicate life forever. Small genetic errors add up, and eventually lead to failure.
Clones have hidden flaws
Cloning works by taking DNA from a body cell and inserting it into an egg cell. This egg then becomes a new animal. The idea is simple, but very powerful.
This technique led to the creation of Dolly the sheep, the first genetically engineered mammal. After that, scientists succeeded in creating mice and other animals.
These clones looked healthy and behaved like normal animals, with no obvious problems. At the time, cloning seemed almost perfect.
Scientists pushed cloning forward
Instead of stopping after creating one clone, the scientists decided to go further. They made a mouse, then used the clone to make another, continuing the process through many generations.
This went on for about 20 years. More than a thousand mice came from the first animal. The first generations did not show any warning signs.
The mice remained healthy and lived normal lives. Nothing seemed wrong. If someone had stopped the experiment there, cloning would have been called a complete success.
The effectiveness of the closure begins to decrease
But time has a way of revealing hidden problems. As generations passed, fewer clones survived.
This approach was unsuccessful. By the time scientists reached the 58th generation, cloning had failed. None of the mice survived.
So what has changed? The answer was not visible from the outside. It was buried deep in DNA.
Small mistakes with big consequences
Each time a clone was created, small changes occurred in the DNA. These weren’t huge or obvious differences, just small shifts that were easy to overlook at first.
However, these small mistakes did not end. They continued to build over time.
Consider playing a game of “telephone,” where a message is passed from one person to another. In the beginning, the message remains the same, but as it progresses, small changes come in. In the end, the message may sound completely different from the original.
That is exactly what happened here. After many generations, the DNA carried many errors. Some mice even lost large amounts of genetic information. At that time, survival became difficult.
Cloning bypasses natural filters
Part of the problem comes from the basics. Cloning uses body cells, not sperm or eggs. These cells are old and degenerating.
Nature usually protects sperm and egg cells very carefully. It also has mechanisms to filter out harmful mutations during reproduction. Cloning appears to violate that protection.
The process itself can also be difficult. Moving DNA from one cell to another is not an easy task. Even small damage can be significant if repeated many times.
Nature has a way of fixing
When artificial mice gave birth in a normal way, their offspring showed improvement. Some damage appeared to be lessening.
This happens because natural reproduction combines DNA from two parents. In some cases, this combination works like a reset.
Harmful changes are not always transmitted in the same way. Cloning does not have this reset method.
Mistakes were beyond repair
Over time, cloning creates many harmful mutations. Scientists have seen that these changes have increased faster than normal reproduction.
At first, the body manages these changes without a problem, but over time, it can no longer deal with the growing damage.
The breaking point comes quietly, then suddenly. That is why the cloning method worked well in the first generations but completely failed later.
Not all damage is visible
Another surprising fact emerges. Most artificial mice looked good. They grew, moved, and lived like other mice. But inside, problems were already emerging.
Their reproductive cells did not function properly, and many of the embryos were unable to develop. Although these issues were not visible at first, the damage was still there.
Cloning is still useful. It could help farmers, protect endangered animals, and even help cure diseases in the future.
However, it also has clear limits. You can’t keep copying life forever without consequences. Errors accumulate over time, and eventually the system begins to fail.
The study was published in the journal Nature Communication.
—–
Like what you read? Subscribe to our newsletter for interesting articles, exclusive content, and the latest updates.
Check us out at EarthSnap, a free app brought to you by Eric Ralls and Earth.com.
—–
#Cloning #reveals #latent #genetic #defects #accumulate #generations