Do clones have belly buttons? Why is there so little mention of cloning now, does the cloned sheep Dolly end badly?

As we all know, the belly button of mammals is the residual part of the umbilical cord, which is a scar left after the umbilical cord falls off, and the function of the umbilical cord is that the mammalian mother delivers oxygen and nutrients to the embryo, and discharges the waste produced by the fetal life process.

So, do clones need something like an umbilical cord and leave a belly button behind?

In some science fiction works, it is indeed mentioned that the way to distinguish a clone is to see if he has a belly button, but this is not the case, and with current technology, only cloned mammals with belly buttons can be created.

How cloning is done

Cloning sounds very high, but in fact it is a precise gene replication technology, which can be some genes, a cell, a tissue, and of course, a higher-end whole animal.

If it is just the precise replication of genes, there are actually many almost perfect cloning technologies in nature, such as the reproduction of single-celled organisms such as bacteria, and identical twins, which are similar to cloning technology.

There are currently two main forms of cloning by scientists, one is called embryonic twinning, and the other is called somatic cell nuclear transfer.

For the first technique, it's more or less artificially creating an identical twin. Simply put, scientists first divide the embryo into two parts and implant the two parts into the recipient's uterus, and then the two embryos will develop into different individuals with common genes.

The second form is much more difficult. Scientists implant the DNA-carrying nucleus of an animal's somatic cell into an egg cell with the nucleus removed. The egg cell then develops into an embryo, which is implanted in the recipient's uterus to develop.

Since the animal's somatic cells contain all the genes of the animal, this means that the embryo carries all the genes of the donor's nucleus, and when it develops in the womb, it is equivalent to a donor that replicates the nucleus.

It is not difficult to find that if an animal is to be cloned, no matter what method scientists use, it will eventually be implanted in the animal's uterus for development.

In other words, the clone develops from the embryo into an individual and is born, it is no different from the normal embryonic development process we usually see, so it will also have a belly button.

Many people may think that clones are like the one above, grown out of nothing in a test tube.

In fact, even this in vitro clone (there should be no such technology now) needs an umbilical cord-like device to deliver nutrients and oxygen, and as long as it does, it will leave a belly button-like scar.

Dolly the cloned sheep who died in pain

In science fiction works, we can often see that clones are very strong and can replace gene donors, or clones directly replace the deity, but this is not the case in reality.

In 1996, Scottish scientists cloned the first animal, known as Dolly the sheep. At that time, scientists extracted the nucleus of adult sheep breast cells. After 276 failures, they finally succeeded in giving birth to one.

Sheep's udder cells are easy to obtain, but every time an egg cell is wasted, the workload is still very large, so you can imagine how difficult it was to get a Dolly at that time. On the other hand, this also shows that it is necessary to clone a whole Being an animal is not easy.

Unfortunately, Dolly didn't do much well, her cells were aging much faster than normal, and she often suffered from a variety of diseases, including lung lesions, arthritis, and more.

Dolly died of illness on February 14, 2003, when she was only 7 years old. Dolly's sheep breed can live around 12 years under normal circumstances, and 7 years is a prime time for them, but Dolly behaves like an old sheep.

After Dolly, scientists have cloned cows, cats, deer, horses and rabbits, and in 2017, Chinese scientists have succeeded in a more difficult primate, the cynomolgus monkey, which seems to be only one step away from cloning humans.

However, almost all cloned animals are similar, their lifespans are basically about half shorter than expected, and various diseases appear in the process of growth.

Some researchers believe that the cloned animals exhibit this condition because the gene donor's telomeres have been depleted during division.

Telomeres are the substances at the ends of chromosomes, and many scientists now believe that human aging is caused by the shrinkage of telomeres, which are shortened every time a cell divides.

Since the cloned gene's donor cells have undergone several divisions, their telomeres have shown a corresponding loss, even if the clones regenerate from the embryo, but this does not change their telomere length.

Can clones completely replace donors?

As we said before, we have the ability to clone primates, so is it possible to clone humans now?

The answer is obvious, of course.

According to the estimates of those pet cloning agencies, cloning a person now costs about 1.7 million US dollars, and its success rate can reach 10% to 20%, which is much higher than Dolly's 1/277.

The main reason why there is no human cloning is that many countries prohibit human cloning, because it is against ethics, and there is not much need for human cloning.

Many people think that clones can completely replicate the original body, and cloning a person is equivalent to having an extra clone.

But in fact, even if there is a clone, he is just a completely independent individual, but it may be very similar in appearance. Just imagine, what is the use of cloning an independent individual who looks like himself, and is weak and sickly.

Human clones are actually a bit like identical twins, but identical twins certainly have different personalities and emotions, and they sometimes look slightly different.

This is because many aspects of human beings are formed, not determined at the genetic level, including our fingerprints, so the drama of clones trying to replace the deity in the movie cannot be staged.

at last

Although human cloning is not allowed or necessary, cloning technology is indeed benefiting the world.

Embryos that scientists create by cloning, for example, can become factories for stem cells, early forms of cells that can grow into many different types of cells and tissues, which are of great medical significance.

In addition, scientists can clone an animal's genes so that livestock like cows and pigs can produce more milk and meat.