Wen | the whole point of science popularization
In 1997, researchers at the Rosslyn Institute in Edinburgh, ENGLAND, published a study in the journal Nature:
The research team led by Dr. Ian Wilmut used cloning technology to successfully breed the first cloned sheep "Dolly" in July 1996.
As soon as the paper was published, it caused a sensation and crazy discussion around the world, and once believed that human beings had found the secret of "immortality".
However, over time, Dolly has hardly heard much about it, and few people have mentioned cloning anymore, why is that?
Clone is an asexual propagation method by artificial intervention in which the nucleus of an egg is removed and implanted into the nucleus of b.
Without mutations in dna, individuals or groups cultured from a will have all the characteristics and genetic structure of b.
The birth of cloning technology is of great significance to stem cell research and the field of medicine, and even comparable to the achievements of the atomic bomb.
However, this technology is not as simple and perfect as imagined, and Dolly's short and pitiful life has awakened human beings.
After the researchers removed the unlieverated egg cell nucleus of the ewe a, the breast cells of the 6-year-old ewe b were put into the egg cells of the ewe a denucleated, and the two were fused by means of electrical stimulation, and the egg cells of the ewe a had the genetic material of the ewe b, forming a new egg cell.
Subsequently, through scientific and technological means, the ewe a new egg cell is promoted to divide, proliferate and grow, and after developing into an embryo, it is moved into the body of the ewe c to continue to develop. In the end, Ewe C gave birth to Dolly.
The researchers conducted 277 embryo experiments, almost all of which were deformed or died prematurely, and only Dolly succeeded, and its birth was not involved in sperm, which means that Dolly has no biological father, only 3 mothers, and the genes are all from ewe b.
Dolly's birth surprised the world, but it wasn't long before researchers discovered new problems.
Scientists have monitored that Dolly was born with short DNA telomeres, frail and diseased, and has very serious congenital diseases.
DNA telomeres reflect the aging process of the species and become shorter with age, which means that Dolly's age does not start from 0, but should be calculated from the maternal age of ewe b.
In 2001, according to the algorithm of human lifespan, Dolly, who was only 5 years old, began to "age": arthritis became more and more serious, lameness occurred, and many diseases that only old sheep had, and her health deteriorated.
On February 14, 2003, at the age of 7, Dolly couldn't bear the pain of severe congenital lung disease and arthritis, and was euthanized every day after being able to extract cells, be monitored, be studied, and genetically defective in the institute.
Supposedly, the normal lifespan of sheep is over 12 years old, and Dolly should be the same, but only lived less than 7 years;
Moreover, dolly, in addition to looking exactly like ewe b, also completely inherited all her diseases, which made scientists suspicious of cloning technology, and all kinds of talk were rampant.
Based on this, the researchers deduced that Dolly's genetic material came from the 6-year-old ewe b, and from the upper limit of Havrik, the number of cell divisions was not from 0, but from the number of times the mother cells had been divided.
So, the moment it was born, it was already 6 years old!
This explains why Dolly, who is not 7 years old, has geriatric disease, because she is actually more than 12 years old!
To test the hypothesis, the Japanese researchers used the same method to clone a pair of twins from bovine somatic cells— "Kaga" and "Noto," and more cloned cattle.
However, some of them were even shorter than Dolly's existence, and they were miscarried or died in a short period of time.
Dolly's pitiful, short life has made scientists aware of a problem: cloning animals may have a really short lifespan.
Moreover, Dolly's appearance has also caused a lot of thinking, especially about "cloning", which is why few people now mention "cloning".
Dolly's success proves that a highly differentiated somatic cell can still re-develop into a new individual even when it returns to the original cell, which is strong evidence for the theory of mammalian somatic cell totipotency; it can also expand the population of animals, and its contribution to the field of medicine is even more amazing.
However, it also creates a lot of problems, and in addition to the speculation of short lifespan, there are two important reasons.
Destroy the diversity of the world
Biodiversity generally relies on sexual reproduction, and half of the female and male genomes form new mixed genes, and various changes occur.
The cloned genes are identical to those of the donor, which is why Dolly and Ewe B are identical in appearance to disease.
Genetic unity is bound to cause species development to be limited, or even to extinction, and maintain biological genetic diversity can go further.
Ethical issues
If cloning were applied to humans, serious moral and ethical problems would arise.
When women do not need men to give birth to one or even countless children exactly like themselves, it will inevitably cause certain social problems;
When everyone wears the same face, things like name and identity may be meaningless: the police can't tell who the real prisoner is, the star who has been declared dead is back on the stage, and the relationship between anyone can be brothers and sisters, parents and elders, but at the same time they are not...
Imagine how terrible it would be if people in the world were exactly the same in terms of intelligence, quality, and physique!
Everyone is a replica, lacking the warmth and cold between human feelings. Moreover, a high IQ is enough, if it is a low IQ, poor physique, etc., this is bound to cause a burden on the entire society.
Moreover, humans cannot guarantee that when cloning technology is applied to humans, cells will not mutate, resulting in pregnancy failure or the birth of a deformed baby.
All in all, human beings will be deeply troubled by ethics and morality, and the social order will also fall into chaos, which is the main reason why "cloning" is rarely mentioned now.
However, cloning is after all a scientific and technological technology that scientists have painstakingly researched after years, and many researchers, although not as open and crazy as before, are still silently continuing to work hard for the better development of mankind.
In 2017, China successfully bred the world's first pair of somatic cloned monkeys "Zhongzhong" and "Huahua".
Their success makes up for the shortcomings of somatic cloning of non-human primates (macaques) similar to humans, helps to build animal models that simulate human diseases, and can also promote the development of new drugs for Alzheimer's disease, autism, etc., using cloning to solve more difficult problems for humans.
There is no right or wrong in technology, only people with hearts. As long as it is used in the right path and beneficial to mankind, then its existence has meaning.
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