The famous Polly and Dolly sheep. The entire scientific world laughed at the cloned sheep Dolly
Simonova Karina
A message on a topical and interesting topic for students: “cloning”
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Ministry of Education and Science of the Russian Federation.
Trudilovskaya
municipal secondary school
Smolensk district, Smolensk region.
Message "Cloning Dolly the Sheep"
10th grade students
Simonova
Karina Sergeevna
Teacher-consultant
Severinova O.A.
2008-09 academic year year
Cloning Dolly the sheep.
Cloning (English cloning from the Greek κλων - “twig, shoot, offspring”) - in the most general sense - the exact reproduction of an object any required number of times. Objects obtained as a result of cloning are called clones. And both each individually and the entire series.
Human cloning is an ethical and scientific problem of the late 20th and early 21st centuries, consisting in the technical ability to begin the formation and cultivation of fundamentally new human beings, accurately reproducing not only externally, but also at the genetic level of a particular individual, currently existing or previously existing - together with the complete ethical unpreparedness of society for this.
The famous sheep Dolly has been diagnosed - rheumatoid arthritis. According to scientists, joint disease is a direct consequence of cloning, reportsBBC .
When cloning from an animalGene disorders could occur, which now led to the disease. Professor Ian Wimouth of EdinburghRoslin Institute stated that the condition of the cloned animal could worsen further. Animal welfare societies considered this news additional evidence that cloning experiments are harmful, and once again demanded that experiments on Dolly be stopped.
Professor Wilmut is convinced that the cause of the disease in a cloned animal cannot be known for sure. However, biologists admit that cases of rheumatism in five-year-old sheep are extremely rare.
Meanwhile, companies that are engaged in research in the field of cloning claim that their “wards” are completely healthy. But, as the BBC notes, there are no independent reports on how cloning affects the condition of animals after several years of life.
The Roslin Institute reports that the death of the sheep was pronounced when a veterinary commission discovered that it had a progressive lung disease.
Dr Griffin says: "The normal lifespan of a sheep is 11-12 years, and lung infections are more common in older sheep, particularly those living indoors." “A full autopsy will be done and the commission will report any significant deviations or changes.”
Dolly was cloned from the breast of a 6-year-old adult sheep and was born on July 5, 1996 at the Roslin Institute.
Her birth was not announced until 7 months later, and the news was immediately hailed as one of the most significant scientific breakthroughs of the decade.
Now she's dead. And her death, regardless of any autopsy results, is unlikely to become a positive argument when the topic of cloning comes up again. Quite the contrary.
It is worth noting that in general, biological achievements in such frontier and revolutionary areas as cloning and genetic modification, so far, instead of the expected panacea for all ills and universal happiness, only cause acute wariness and conflicts on moral, ethical and religious grounds. Although this may just be a pessimistic view of what is happening. But what a reason, such a look.
The life and death of Dolly the sheep.
This, or almost this, would be the message about Dolly’s death if she were human. But Dolly is just a sheep who got very lucky. The lucky thing is not that it is the most famous sheep in the world, with the possible exception of the lamb that “Mary had,” but that Dolly is the first surviving clone of a large mammal in the history of biotechnology. Before her birth, scientists from the Roslin Institute and PPL Therapeutics made about 300 unsuccessful cloning attempts. As they say, most of the cloned embryos died before even reaching the womb of the surrogate mother, and those that reached birth did not at all resemble successful experiments. And sometimes on sheep too.
The birth of Dolly had the effect of a bomb exploding. The authoritative magazine Nature in February 1997 put the heroine on the cover and dedicated a large article to her, and many simpler publications became a platform for skeptics and a rumor factory. There were many rumors. So, from the very appearance of Dolly, they said that the sheep ages at an alarming rate. As evidence, data was cited on Dolly's diseases, which, it was argued, were either not characteristic of sheep at all, or did not appear in sheep of her age. During the foot-and-mouth epidemic, it was reported that Dolly would be slaughtered - along with the rest of the British sheep population. In addition, some wild evidence appeared about Dolly's unusual aggressiveness - apparently, the authors of these versions believed that a berserker sheep as a reason for a newspaper headline was more interesting than the result of a unique scientific experiment.
The press repeatedly reported that Dolly had died (the last time this happened two weeks before her actual death). Some news agencies, commenting on the death of her technological sister Matilda, cloned by Australian scientists, stated that Matilda may have died from the same misfortune as Dolly. From rapid aging.
Adding fuel to the fire is the fact that scientists involved in cloning are, as a rule, quite closed and in no hurry to reveal their own secrets. Everyone intuitively understands what enormous money this technology promises if it is put into production. About Dolly, who was born in 1996, became known only six months after her birth. And Matilda - if you believe the official version - was not even subjected to an autopsy and was immediately cremated. The grounds for cremation are ridiculous. Rob Lewis, chief executive of the South Australian Institute of Scientific Research, said the sheep "stank".
Another reason to remain silent regarding the lambs was given by Dolly's creator Ian Wilmut - many researchers do not want to publish preliminary research results because they know how ambivalent the public is about cloning and do not want to once again escalate the tension.
As for the reporters who rushed to bury Dolly, they almost got it right. By the time of Matilda's death, Dolly was already seriously ill. Unlike the suddenly cremated Matilda, the world's first clone will serve science even after death. The Roslin Institute promised that the sheep would be exhumed and the results of the post-mortem examination would be published.
Was Dolly doomed?
We have to admit that the skeptics were right to some extent and their statements about Dolly’s rapid aging, based on the assumption that the cells of a six-year-old donor remained six years old after the transplant, look more plausible today. Researchers from the Roslin Institute have never directly confirmed such suspicions, often ignoring them, however, judging by the statements, they admit the possibility that the donor cells were unable to rebuild and the biological age of the cells of the newborn sheep exceeded six years.
Let's start with the fact that Dolly died very early. Sheep usually live 11–12 years (maximum - up to sixteen), so if we assume that Dolly was born six years old, then her death can easily be explained by banal old age. The Roslin Institute acknowledges that the lung disease that caused the death is usually found in older sheep and is rare in six-year-old sheep. Since 2001, Dolly is known to have suffered from arthritis, another condition that is rare in sheep in their "prime of life."
Commenting on attempts at human cloning, Harry Griffin from the Roslin Institute said that he opposes such research at the current stage of scientific development. According to him, human clones are unlikely to turn out healthy, therefore, it would be better to stop experiments on their creation for now. Moreover, Griffin believes that "clones have a huge number of physical abnormalities, and even if they appear healthy, this does not mean anything." And even more specifically (and almost in unison with the skeptics): “Try to convince the forty thousand genes contained in a cell that this cell belongs to an embryo, and not an adult. We don't know how to reprogram genes, and failures are possible here. We have already encountered this problem when cloning animals, and where is the guarantee that the same problems will not arise when cloning people?
Human cloning legislation
In some countries, the use of these technologies in relation to humans is officially prohibited - USA, France, Germany, Japan. These prohibitions, however, do not mean the intention of legislators of these states to refrain from using human cloning in the future, after a detailed study of the molecular mechanisms of interaction between the cytoplasm of the recipient oocyte and the nucleus of the somatic donor cell, as well as improving the cloning technique itself.
On February 19, 2005, the United Nations called on UN member states to pass legislation banning all forms of cloning as they are “contrary to human dignity” and are against the “protection of human life.” The UN Declaration on Human Cloning, adopted by General Assembly resolution 59/280 on 8 March 2005, calls on Member States to prohibit all forms of human cloning to the extent that they are incompatible with human dignity and the protection of human life. At the same time, efforts to adopt a universal international agreement to ban cloning within the UN have not yet been successful.
The only international act to date that establishes a ban on human cloning is the Additional Protocol to the Convention for the Protection of Human Rights and Human Dignity in Connection with Biology and Medicine, relating to the prohibition of the cloning of human beings, which was signed on January 12, 1998 by 24 countries out of 43 countries. members of the Council of Europe (the Convention itself was adopted by the Committee of Ministers of the Council of Europe on November 19, 1996). On March 1, 2001, after ratification by 5 countries, this Protocol entered into force.
Although Russia does not participate in the above-mentioned Convention and Protocol, it has not remained aloof from global trends, having responded to the challenge of the time by adopting the Federal Law “On a temporary ban on human cloning” dated May 20, 2002 N 54-FZ.
As stated in its preamble, the law introduces a temporary (for a period of five years) ban on human cloning, based on the principles of respect for people, recognition of the value of the individual, the need to protect human rights and freedoms, and taking into account the insufficiently studied biological and social consequences of human cloning. Taking into account the prospects for using existing and developing technologies for cloning organisms, it is possible to extend the ban on human cloning or lift it as scientific knowledge in this area accumulates and moral, social and ethical standards are determined when using human cloning technologies.
The Law defines human cloning as “the creation of a human being genetically identical to another living or deceased human being by transferring the nucleus of a human somatic cell into a denucleated female reproductive cell,” i.e. We are talking only about reproductive cloning, not therapeutic cloning.
According to Art. 4 of the Law, persons guilty of violating it are liable in accordance with the legislation of the Russian Federation.
Currently, the process of criminalization of human cloning is actively unfolding in the world. In particular, such compounds are included in the new criminal codes of Spain 1995, El Salvador 1997, Colombia 2000, Estonia 2001, Mexico (Federal District) 2002, Moldova 2002, Romania 2004). In Slovenia, a corresponding amendment to the Criminal Code was made in 2002, in Slovakia – in 2003.
In France, amendments to the Criminal Code providing for liability for cloning were made in accordance with the Bioethics Law of August 6, 2004.
In some countries (Brazil, Germany, Great Britain, Japan) criminal liability for cloning is established by special laws. For example, the German Federal Embryo Protection Act of 1990 makes it a crime to create an embryo that is genetically identical to another embryo derived from a living or dead person.
In the UK, the relevant criminal provisions are contained in the Human Reproductive Cloning Act 2001, which provides for a sanction of 10 years' imprisonment. However, therapeutic human cloning is permitted.
In the United States, a ban on cloning was first introduced back in 1980. In 2003, the US House of Representatives passed a law (Human Cloning Prohibition Act of 2003), according to which cloning aimed at both reproduction and medical research and treatment is considered as a felony with a possible 10-year prison sentence and a $1 million fine.
Finally, in Japan, on November 30, 2000, the Diet passed the “Law Regulating the Use of Human Cloning Technology and Other Similar Technologies,” containing the necessary criminal sanctions.
I decided to remember the fate of the most famous sheep in the world and asked which animal scientists had managed to clone recently.
DOLLY THE SHEEP AND HER SAD STORY
On July 5, 1996, in the city of Mithlodian, Scotland, the world's first cloned animal, a mammal, at least officially cloned, was born. The press learned about the powerful breakthrough in genetics only seven months after the birth of the sheep.
As it turned out, Dolly was one of many attempts by scientists to clone a living organism. Before the famous Dolly, the same group of scientists cloned the sheep Megan and Morag. Articles about them were published in the journal Nature in 1997, but they died almost immediately, so these attempts were announced only after the successful cloning of Dolly.
HOW DOLLY WAS BORN
As indicated in the experimental protocol, in the process of creating Dolly, nuclei from non-reproductive cells were added to 277 eggs, after which 29 embryos were formed, of which only Dolly survived. It owes its appearance to the technology of somatic cell nuclear transplantation. That is, Dolly was the result of a transplantation of the nucleus of a somatic cell into the cytoplasm of an egg. Dolly the sheep was a genetic copy of the cell donor sheep.
DOLLY'S "PARENTS"
The experiment was carried out by Ian Wilmut and Keith Campbell at the Roslyn Institute in Scotland. The authors of the Dolly experiment published a book: "The second creation: Dolly and the age of biological control." Cambridge, Mass.: Harvard University Press, 2001.
In 2013, Professor Keith Campbell, who was one of the fathers of the first successful cloning of Dolly the sheep in 1996, accidentally killed himself while heavily intoxicated. The body of the 58-year-old geneticist was discovered on October 5, 2012 in the bedroom of his home, he hanged himself with his own belt. As it turned out, he was drunk and wanted to scare his wife.
HISTORY OF THE NAME OF THE CLONED SHEEP
The sheep was initially assigned the identification code 6LL3. She received the name Dolly only a few months after cloning, when scientists were convinced that the animal was viable. The sheep was named after the American country singer Dolly Parton at the suggestion of one of the veterinarians who helped scientists at the birth of the sheep.
According to media reports, the sheep was named Dolly not just because of the veterinarian’s love for the singer’s work. The sheep was obtained from an udder cage, which is why it received the name of the American singer Dolly Parton, who loved to focus attention on her large bust. Whether this is true or a myth is still unknown...
THE DEATH OF DOLLY
The cloned sheep lived only six years, although the average age of this species is 10-12. Dolly died on February 14, 2003 from a progressive lung disease that was caused by a retrovirus. Such diseases most often appear only in old sheep. However, scientists still have no evidence that the cause of the disease was premature aging. Rumor has it that Dolly developed this disease due to the fact that she was constantly kept indoors and hardly walked, which is a necessary factor for the longevity and health of sheep. Dolly also suffered from arthritis for several years due to excess body weight. After concluding that both diseases would kill the animal, the decision was made to euthanize her. During her life, Dolly managed to give birth to six lambs and became the favorite of many scientists and people.
THE SIGNIFICANCE OF DOLLY CLONING AND ITS CONSEQUENCES
After the success with Dolly, scientists conducted experiments on cloning various mammals: horses, bulls, cats, dogs. They also used the technology of replacing oocyte nuclei with nuclei of somatic cells taken from living adult warm-blooded animals (mouse, goat, pig, cow). Experiments were also carried out using the same technology with cloning frozen dead animals.
Despite the criticism, scientists have made it clear to the world that cloning can be used both to preserve endangered species and to reproduce transgenic, artificial species and breeds. But simple methods like those used to create Dolly cannot solve the problem of genetic diversity. To solve it, it is necessary to develop more expensive and flexible approaches. Scientists also do not give up hope of reviving extinct animal species using the cloning technique.
After the appearance of Dolly, the topic of cloning raised a number of ethical and philosophical questions for society. The media began talking about human cloning, which was critically viewed by representatives of different religions, churchmen, philosophers and politicians.
Some governments have limited funding and support for cloning research. And parliaments banned research and development directly aimed at human cloning.
It is known that there are entire “clone factories” in China, which the government prefers not to talk about. There are constantly reports in the media about successful cloning of dogs and livestock by Chinese scientists. True, such centers are illegal and are constantly exposed.
CHRONOLOGY OF ANIMAL CLONING:
1970 - successful cloning of a frog
1985 - cloning of bony fish
1987 - first mouse
1996 - Dolly the sheep
1998 - first cow
1999 - first goat
2001 - first cat
2002 - first rabbit
2003 - first bull, mule, deer
2004 - first experience of cloning for commercial purposes (cats)
2005 - first dog (Afghan hound named Snoopy)
2006 - first ferret
2007 - second dog
2008 - third dog (Labrador named Chase). Cloned by government order. Commercial dog cloning begins
2009 - the first successful cloning of a camel. Also, for the first time in the Middle East (namely Iran), a goat was successfully cloned
2011 - eight cloned coyote puppies
DOLLY'S FOLLOWERS: POLLY AND MOLLY
Polly and Molly were the first cloned sheep to be successfully introduced with a human gene for possible medical use. For this purpose, special technology developed by Keith Campbell was used. Successful cloning was announced in July 1997. Two of the three sheep survived and were named Polly and Molly, after the world's first sheep, Dolly, cloned in 1996.
Scientists dreamed that thanks to such a symbiosis of genes they would be able to treat people and save lives, but, as the study showed, at that stage of the development of genetics such an experiment was unsuccessful. They say that the sheep did not even live a year, because the human gene killed them.
THE FIRST CLONED DOG IN THE WORLD - SNUPPY
On April 24, 2005, the first cloned dog, Snoopy, was born. This happened at Seoul National University. It was from the name of the establishment in combination with the word puppy (from English - puppy) that he received his nickname.
The Afghan Hound puppy was born under the guidance of Professor Sok Hwan. He created one thousand ninety-five cloned embryos, which were then implanted into 123 “surrogate mothers.” Confirmation of pregnancy was obtained in only three of them, and one of the pregnancies ended in miscarriage. Of the two newborn puppies, one died of pneumonia at the age of three months, and the second - that same Snoopy - can boast of a rather eventful life: in 2008, he became the happy father of nine puppies (there were ten in the litter, but one died almost immediately).
The donor of the genetic material, and therefore the “original” for Snoopy himself, was a three-year-old Afghan hound dog, Tai, whose DNA was isolated from ear skin cells. The egg was taken from a mixed-breed dog, and a female Labrador retriever became the surrogate mother for the puppy.
So far, the media has no information about the death of the first cloned dog. It is only known that in addition to successful fatherhood, Snoopy lives the ordinary life of an ordinary dog.
Rumor has it that the scientist Seok Hwana subsequently resigned from the university and began his own research with human embryos, which caused a lot of noise in the research community. After a successful experiment with a dog, a team of scientists from Seoul University managed to clone 30 dogs and 5 wolves.
In 2007, search dogs were cloned for the first time. All seven clones were named Toppy. These dogs entered service with South Korean customs in July 2009. The project was financed by the South Korean government, the project cost about 300 million South Korean won.
Since 2004, commercial cloning of cats began in the United States, and since 2008, all dog owners who have lost a pet can also recreate their pet dog for a lot of money.
THE CAMEL INJAZ AND HER FATE
On April 8, 2009 in the UAE, at the Dubai Camel Reproduction Center, the first cloned female camel was born - Injaz ("Achievement" in Arabic). Dr Nisar Ahmad Wani, a reproductive biologist and head of the centre's research team, said the first cloned female camel was born after an "uncomplicated" pregnancy of 378 days.
After a successful experiment with Dolly, Dubai scientists began to study the experience of their colleagues from Britain. The program was funded at the state level by one of the UAE emirs.
Injaz was created from ovarian cells from an adult camel killed for meat in 2005. The cells were grown in tissue culture and then frozen in liquid nitrogen. After this, one of the cells was introduced into the nucleus-deprived egg of a surrogate camel, in which division was initiated under the influence of electric current and chemical induction. As a result, the embryo was cultured for a week and then implanted back into the uterus of the surrogate camel.
Twenty days later, her pregnancy was confirmed by ultrasound examination and was monitored throughout the pregnancy. After Injaz was born, her DNA was tested in the laboratory and her DNA identity was officially proven.
Let us note that camel racing in the UAE is a profitable business, and therefore purebred champion camels, which, unfortunately, do not last forever, are very valuable, and their clones are priceless.
According to scientists, after successfully cloning Injaz and observing her life, which was no different from the life of camels born naturally, camel cloning in the UAE became more widespread.
Wolves Snoowolf and Snoowolfie
In 2006, South Koreans from Gyeongsan National University succeeded for the first time in cloning wolf cubs, which later received the names Snoowolf and Snoowolfie. The main purpose of cloning was to preserve the endangered species, since no more than 10 wolf individuals lived in the wild in Korea at that time. Cloned wolves were available for public viewing - they were shown at the Seoul Zoo. One of them, unfortunately, died from an infection right in front of visitors.
AFTERWORD. Thanks to the achievements of genetic scientists, the world learned about what cloning is. If earlier humanity knew about such experiments only thanks to science fiction writers and Hollywood films, now every educated person understands that thanks to the cloning technique, many opportunities open up for society. Of course, I would like to believe that such experiments and achievements of scientists serve only a useful purpose, such as saving lives, preserving endangered species and restoring extinct animal species. But in no way would I want science to serve only the financial interests of power structures or to satisfy the needs of wealthy people who dream of “reviving” their beloved cat or dog. It is also terrible to imagine “cloning factories” in Asian countries, where animals are kept in unbearable conditions, and in order to achieve “ideal cloning” they forget about the human attitude towards our smaller brothers.
Why the biologists who were the first to clone a large mammal were not given the Nobel Prize, why one of them unsuccessfully staged suicide, the reason for Dolly’s short life and what the magnificent bust of the American singer has to do with it, the site explains in the “History of Science” section.
On July 5, 1996, in the Scottish city of Midlothian near Edinburgh, a lamb was born, which, by the mere fact of its birth, became a world-class star, and not only a scientific one. The sheep, as the reader remembers even without reminders, was named Dolly, and soon she became the most famous clone. True, Dolly received megastar status only seven months after her birth.
Her creators, Roslyn University professors Ian Wilmut and Keith Campbell, after many unsuccessful attempts, decided not to pull fate by the tail and remained silent until they were finally convinced that Dolly was not only born, but also a full-fledged healthy individual. They say that this delay was required by scientists in order to obtain a patent. So it was only on February 22, 1997 that both the sheep and its creators woke up famous.
In fact, Dolly was not the first at all. The same Wilmut and Campbell in 1996, through the journal Nature, announced the birth of sheep Megan and Morag. This was not so much a successful attempt at cloning an animal as it was an intermediate step towards a true clone, since both of these sheep were derived from embryonic cells, meaning they had both a dad and a mom. Dolly was a copy of her mother, a Finn Dorset sheep, who was long dead by the time her genetic copy was born. The most important difference between Dolly and Megan and Morag was that she came from the somatic cells of an adult animal, and her genome was almost exactly the same as her mother's. We’ll talk about this “almost” a little later.
During the experiment to create Dolly, biologists transferred the cell nuclei of a donor sheep into 277 eggs, from which their own nuclei with genetic material had previously been removed. All these nuclei were kept frozen before the experiment, and only a tenth of them, after thawing, were able to develop into an embryo. Of the 29 embryos, only one survived - the one taken from the udder of the prototype sheep. In particular, they claim that this is why she received the name Dolly. The fact is that one of the veterinarians who helped the scientists suggested naming the sheep after Dolly (Doll) in honor of the American country singer Dolly Parton, who became famous not only for her songs, but also for her bust, the splendor of which she invariably emphasized. So it was not her talent that immortalized the name Dolly Parton.
American singer Dolly Parton
Fred Prouser/Reuters
By the way, Louis Armstrong’s famous hit Hello, Dolly has nothing to do with Dolly Parton; the legendary Satchmo performed it for the musical based on Thornton Wilder’s story “The Matchmaker,” the heroine of which was the singer’s namesake.
One success for 276 failures - this ratio would cool anyone, but not Wilmut and Campbell, since this chance, small as it was, promised the researchers a Nobel Prize, which, however, they never received. Keith Campbell did not wait for the prize, dying an anecdotal death (being drunk, he decided to shock his family with a fake suicide by hanging, but miscalculated and hanged himself seriously), and the still alive Jan Wilmut had also not yet received news from Sweden.
Dolly the Sheep
Jeff J Mitchell UK/Reuters
Some scientists compare this achievement to the splitting of the nucleus, while others compare it to the discovery of the structure of DNA by Watson and Crick. However, not all scientists agreed to consider Dolly a clone of a single mother, which is perhaps why the prize has not yet been given. The fact is that Dolly has three mothers, because the unfertilized eggs from which the nuclei were extracted were taken from one sheep, the nuclei from another, and Dolly was carried by the third - the surrogate - mother. Thus, Dolly the sheep, without having a single father, managed to become the daughter of three mothers at once.
However, the lack of a Nobel million did not prevent researchers around the world from starting the production of cloned animals according to the recipe of Wilmut and Campbell. This recipe, scientifically called “nuclear transfer,” has been improved over time, and today cloning an animal using it does not require hundreds of frozen DNA, of which only one will work.
Immediately after the information appeared that it was possible to clone warm-blooded animals, a real boom began all over the world. Using Scottish technology, scientists in many countries began cloning a wide variety of animals, including horses, bulls, cats, dogs, camels, etc. Also, using the same technology, attempts were made to genetically reconstruct extinct animals, whose bodies continued to be stored in frozen form. In the future, scientists say, it is even possible to reconstruct long-extinct animals, such as a mammoth or a dinosaur.
The only warm-blooded animal that many countries decided to leave alone and not clone is humans. That is, it is clear that such cloning is also technically feasible, although in this case many questions arise, affecting both ethics and religion. However, this prohibition is constantly violated by one researcher or another, each of whom eventually turned out to be a charlatan. Today, in many countries, including Russia, human cloning is prohibited by law.
1. Animal Cloning
The term "clone" comes from the Greek word "klon", which means twig, shoot, offspring. Cloning can be given many definitions, here are some of the most common ones: cloning is a population of cells or organisms descended from a common ancestor through asexual reproduction, and the descendant is genetically identical to its ancestor.
The cloning process itself can be divided into several stages. First, an egg is taken from a female individual, and the nucleus is extracted from it using a microscopic pipette. Another one containing the DNA of the cloned organism is inserted into the anucleated egg. From the moment the new genetic material merges with the egg, the process of cell reproduction and embryo growth is expected to begin. Such expectations are based on at least two clear scientific motivations. The first is the desire to find out how intact the genetic material remains during the development of an organism that has a characteristic fate. The second motivation is to what extent are the factors in the cytoplasm of the egg itself compatible with the genetic material brought into it for reprogramming - for example, does it matter if the foreign genes and the own genes of the mitochondria of the egg are different? Many similar questions arise. Let us turn to the history of research into attempts to clone animals.
Dolly the Sheep
In February 1997, humanity was shocked by the news from the Scottish Roslin Institute about the birth and normal development of the first mammal obtained by nuclear transfer, or, more simply, cloning - Dolly the sheep. Perhaps this event had an effect similar to the announcement of the invention of the nuclear bomb or the emergence of television.
First, a cell was taken from the mammary gland of an adult sheep and the activity of its genes was extinguished using artificial methods. The cell was then placed in an embryonic environment called an oocyte to rewire the genetic program for embryonic development. Meanwhile, the nucleus was “pulled out” from the egg of another sheep, and after cooling the cytoplasmic membrane under the influence of an electric field, the nucleus isolated from the mammary gland cell of the first sheep was introduced into it. The egg fertilized in the manner described above was placed in the uterus of the third sheep - the surrogate mother. And after the usual gestation process, Dolly the sheep was born, which was a complete genetic copy of the sheep - the donor of the mammary gland cell.
A rumor that spread with incredible speed almost from the moment Dolly's existence was announced was that a cloned sheep ages several times faster than its “normally born” relatives.
These data, as it turned out, are largely true. One of the most likely explanations for this phenomenally rapid aging is that it occurs due to a programmed limitation on the number of divisions and lifespan of each cell in higher organisms. Talk about Dolly's reproductive disorders has no basis at all. .
No real reason, since she had already given birth safely at least twice, giving birth to her first child, Bonnie, in her second year, and three healthy lambs a year later.
Dolly the sheep lived for 6 mostly painful years.
Cloning 5 piglets
In 2000, British scientists who cloned Dolly the sheep created five piglets using the same method. Specialists from PPL Therapeutics performed the operation in the American city of Blacksburg. Cells from an adult pig were used as a basis.
All piglets bred are female and all are healthy.
Experts believe that in this way in the future it will be possible to produce pigs, whose organs will subsequently be used for transplantation into people. It is expected that scientists will conduct the first experiments in this area within four years.
The possibility of cloning opens up quite a lot of prospects for us, but we also face a lot of disputes and disagreements.
2. Therapeutic cloning
When it comes to human cloning, the process is prohibited by law in many countries due to many aspects.
But there is such a type of cloning as therapeutic. Therapeutic cloning uses a process known as somatic cell nuclear transfer (nuclear transfer, research cloning, and embryo cloning), which involves removing an egg from which the nucleus has been removed and replacing that nucleus with DNA from another organism. After many mitotic divisions of the culture (culture mitoses), a given cell forms a blastyst (an early stage embryo consisting of approximately 100 cells) with DNA almost identical to the original organism.
The purpose of this procedure is to obtain stem cells. genetically compatible with the donor organism.
Is it possible, under special conditions, to reproduce a genetically exact copy of any living creature? The symbol of the first cloned mammal (1996) was Dolly the sheep, who suffered throughout her life from pneumonia and arthritis and was forcibly euthanized at the age of six - an age equal to about half the average life of a normal sheep. Cloning animals has not proven to be as easy as cloning plants.
Therapeutic cloning uses a process known as somatic cell nuclear transfer.
2.1 The Prospect of Therapeutic Cloning
Stem cells obtained through therapeutic cloning are used to treat many diseases. In addition, a number of methods using them are currently under development (treatment of certain types of blindness, spinal cord injuries, etc.)
This method often causes controversy in the scientific community, and the term describing the created blastocyst is called into question. Some believe that it is incorrect to call it a blastocyst or embryo since it was not created by fertilization, but others argue that under the right conditions it can develop into a fetus, and ultimately a child - so it is more appropriate to call the result an embryo.
The potential for therapeutic cloning in the medical field is enormous. Some opponents of therapeutic cloning object to the fact that the procedure uses human embryos and destroys them in the process. Others feel that such an approach instrumentalizes human life or that it would be difficult to allow therapeutic cloning without allowing reproductive cloning.
3. Meaning of cloning
Currently, the methods of genetic engineering and, in particular, cloning are associated with many hopes in the field of treatment of previously incurable diseases, reproduction and organ transplantation, and in the field of artificial conception, the fight against disability and congenital defects... More and more experiments are being carried out on the cultivation of mammals and subsequent transplantation of their organs to humans. More recently, South Korea managed to clone a piglet, whose genetically modified cells can reduce the threat of organ rejection by the human immune system during transplantation by 60-70%. And in light of the problem associated with the inability to have children, artificial insemination methods have received widespread support in society. As for cloning itself, it allows the same procedures to be carried out using the gene pool of only one of the parents, which is often necessary if one of the parents is predisposed to serious diseases.
Pancreatic cell transplantation will relieve diabetic patients from constant insulin injections and the need to follow a strict diet. British surgeon James Shapiro, who successfully performed the first eight operations, reported this at a conference in Chicago.
Purified pancreatic cells from healthy donors were administered intravenously to diabetic patients. These cells lingered in the liver, where they continued to produce insulin. In eight patients aged from 29 to 53 years, the need for insulin injections disappeared in the immediate postoperative period.
British Diabetes Association spokesman Bill Hartnett says the new treatment is extremely promising, but warns against jumping to conclusions because the results of the cell transplant have not yet been published. Patients after this operation must constantly take immunosuppressants to prevent rejection of the transplanted cells. The development of the cloning method will in the future solve the problem of obtaining a sufficient number of pancreatic cells, James Shapiro said at the conference of the American Society of Transplantation.
Cloning technologies were first used to save endangered species. Next month, scientists expect the birth of a baby gaur (a type of Asian ox), which was carried by an ordinary cow. The embryo itself was created in the laboratory from a cow's egg and genes taken from the skin of a gaur.
On the other hand, the question is often raised that cloning can reduce genetic diversity, making humanity more vulnerable, for example, to epidemics, which, according to the most pessimistic forecasts, will lead to the death of civilization.
Doubtful "paternity" of Dolly the sheep
Jan Wilmut and Dolly the Sheep
Since an article about the cloning of Dolly the sheep was published in Nature magazine in 1997, scandals have not subsided around her. The scientific purity of the experiment, its value, and the ethical side of cloning were questioned. Even after the first artificially created mammal died and its stuffed animal was exhibited at the National Museum of Scotland, Dolly and her creators continue to remain under the radar of journalists.
The word “clone” appeared long before geneticists produced the first artificial animals. Translated from Greek, it means “descendant.” If we omit the details, the essence of cloning technology is this: the nucleus is removed from the egg, and in its place the nucleus of another cell is introduced - a somatic one, and after some time an embryo is formed from it. In germ cells, as is known, the set of chromosomes is half. By replacing it with a complete set from the somatic cell of a donor animal, it is possible to grow its exact copy. At least it seemed so until recently. But perhaps scientists were too hasty in announcing a new achievement...
Dolly was born on July 5, 1996. Its “prototype” was a Scottish Blackface sheep named Finn Dorset - it was from its udder that the cage that became the basis of the first clone was taken. And the “surrogate mother” was a sheep of the same breed, Bleifex. It should be noted: Dolly was not the world's first clone. The first successful experiments in cloning animals were carried out in the mid-1970s by the English embryologist J. Gordon. Nor was she the first clone of a mammal: scientists from the Rosslyn Institute (Scotland) debuted two lambs born by replacing the nuclei of eggs with the nuclei of embryonic cells. Dolly's championship lies elsewhere: a group of scientists led by Jan (Ian) Wilmut was the first to succeed in cloning a mammal using a somatic cell from an adult animal. After a complex operation was performed to replace the nucleus of the egg, it began to divide. And six days later the embryo was transferred into Blackface's uterus. The result was the birth of an absolutely exact copy of Finn Dorset - at least that's what scientists said. However, they were in no hurry to publish the result of the experiment - first they had to make sure that the clone was developing normally and did not have any abnormalities. After all, until that time, geneticists had only been able to create clones of frogs, but they lived only to the tadpole stage. In addition, scientists were apparently afraid of public outcry - after all, until now the creation of a new life was shrouded in secrecy, and interference in this process was seen as sacrilege.
The fears turned out to be not in vain. As soon as the result of the experiment was made public, it became a real sensation not only in the scientific world, but also in popular publications. And following a wave of articles about the revolution in biotechnology, fierce debate began about the ethical side of cloning. The main reason for these disputes was that birth in all religions was considered an act of divine creation. Cloning a mammal (no one doubted that Dolly the sheep would be followed by other animals, and later by people) could seriously affect faith, causing thousands of people to doubt the truth of religion. However, the real scandal broke out only after scientists announced their desire to clone human cells. The Pope unequivocally spoke out in favor of a ban on such experiments. He was supported by many public figures. Despite the benefits that cloning promises (growing new organs from the patient’s own tissues, increasing life expectancy, etc.), it can create huge psychological and ethical problems. In fact: if it is possible to clone a person, who will his clones be considered? Full-fledged people? But then they cannot be “disassembled” for donor organs. An artificially grown set of cells? But clones are an exact copy of their “donors” and differ from them only in the lack of life experience. This is not a complete list of questions that the birth of Dolly the sheep posed to humanity. However, soon the believers breathed a sigh of relief: it turned out that man was still far from reaching the Creator.
Cloning Dolly marked the beginning of a whole series of experiments. Both serious scientists and wealthy amateurs entered into an unspoken competition to see who would surprise the world the most. There were numerous reports that scientists had successfully cloned a variety of animals: piglets, pigs, dogs. However, upon careful examination, it turned out that in most cases it was not about cloning at all.
Experts were alarmed by one detail: almost all (except for the stallion Prometheus, which appeared in the Italian city of Cremona) of the cloned animals were for some reason female. This gave rise to suspicion. The fact is that biologists know a method for obtaining genetic copies that has nothing to do with cloning itself. We are talking about parthenogenesis. It is somewhat simpler to carry out than cloning: with the help of chemicals, scientists stimulate the division of the egg and the formation of an embryo without fertilization (in nature, this phenomenon is observed in daphnia, aphids and bees). True, only females can be born this way. Maybe most clones are the result of parthenogenesis?
Questions were raised not only by the gender of the newly created clones, but also by a huge number of dubious experiments. Thus, American scientists announced that they were able to clone three piglets from the ear of an adult boar. But independent experts were never allowed to approach them, and the photographs published in the magazine could have depicted any twin piglets, so they cannot be considered evidence. An even stranger incident occurred with the Soru Cat company, which announced a new service to pet lovers. They set about cloning pets. But the kitten shown on TV differed in color and pattern from its “original”, which gave rise to doubts about the purity of the experiment. True, geneticists explained the discrepancies by saying that “the genotype does not affect color.”
During the checks, the scientists' attention also came to Dolly. And several details emerged that made us think seriously about the future of cloning. It turned out that the famous sheep Dolly was still different from the “original”, and not for the better. This information reached the Russian-speaking scientific world thanks to scientist German Malinichev, who declared a year after the sensation: “The sheep Dolly, cloned last year by English scientists, is becoming a monster.” The scientist, citing Scottish sources, said that Dolly the sheep became aggressive, bit the employees who looked after her several times, and almost crippled the young sheep left with her in the pen. True, at that moment Dolly was pregnant, and they tried to explain her behavior precisely by this. Although many experts openly stated that such aggression cannot in any way be explained by the “interesting situation” of the sheep. By the way, Dolly quite successfully coped with the birth of lambs, whose father (this time - the real one) was the Welsh mountain ram David. Bonnie was born in April 1998, followed by three more lambs the following year. But after their birth, Dolly's health began to deteriorate.
In 2002, scientists were surprised to discover that Dolly was showing signs of arthritis, a condition common in older sheep. The average lifespan of sheep is 11–12 years, so Dolly was in her prime. Analyzes showed that the cloned sheep began the process of premature cell aging. And in 2003, Dolly was diagnosed with a serious lung disease. After this, they decided to euthanize the sheep. She died on February 14, 2003, having lived less than seven years.
The experimenters were immediately bombarded with questions: was Dolly’s premature aging related to her “artificial” origin? Jan Wilmut, one of the creators of the clone, initially strongly rejected this assumption: “It is unlikely that Dolly’s illness has anything to do with the cloning technology itself. A much more obvious explanation is that in the animal world, just like in the human world, there are very unpleasant and serious diseases. It is quite possible that the infection entered her body naturally.” But data obtained by other experimenters soon confirmed a sad fact: cloned animals, despite almost complete genetic identity, are much more susceptible to various pathologies than their naturally born counterparts. The most striking evidence was the cloning of monkeys. It turned out that the nuclei of embryonic cells are formed incorrectly: the number of chromosomes in them differs from the norm. As a result, already on the sixth or seventh day, the embryos begin to look abnormal. The monkey supposedly successfully cloned by the Americans - a rhesus macaque named Tetra - turned out to be an ordinary macaque, and the embryo obtained after 724 attempts was so seriously different from the usual ones that the experiment was stopped.
What made scientists commit a forgery? The answer is simple and cynical: money. Today it is estimated that the production of one clone costs three to four million dollars - taking into account the costs of “defects”. After all, not all “operated” cells develop normally. When scientists conducted an experiment to clone Dolly, they transplanted 277 cells, and only 29 embryos managed to live more than six days. One of the main areas of work of research groups is the search for methods that can reduce the cost of clones. And considerable grants are allocated for these searches - millions of dollars. This is a serious temptation for unscrupulous scientists: after all, declaring to the whole world about another success, they can rightfully demand continued allocations.
After the death of Dolly the sheep, the number of articles about her decreased. But in 2006, this project became the focus of a new scandal, this time related to Jan Wilmut. The scientist appeared in court on a rather serious charge. His former colleague Prim Singh said that Wilmut had illegally appropriated the fruits of collective work. During the trial, words were heard about persecution on racial grounds, which in the modern world is considered a much more serious violation of the law than falsification of experimental results. Wilmut categorically denied this accusation, but was forced to admit that the Dolly cloning experiment was 66% the work of another specialist. However, this “other” was not the initiator of the trial, Prim Singh, but Keith Campbell. It was this scientist, now working at the University of Nottingham, who first came up with the idea of coordinating the cycles of a denucleated recipient cell and a cell whose genetic material was intended to be cloned.
Scandals related to the authorship of this or that scientific idea, unfortunately, have a long tradition. Even the famous Louis Pasteur, who created the anthrax vaccine, as it recently turned out, took advantage of the fruits of the work of his colleague, Charles Chamberlain. It was his vaccine, the preparation of which differed from Pasteur’s, that helped cure a flock of sheep from anthrax. And Newton, the founder of the doctrine of heredity Mendel, and Sigmund Freud were involved in “combing” the results obtained. Is it possible to stop this practice? Today, unfortunately, there are no reliable methods. And we can only rely on the consciousness of the scientists themselves and corporate ethics. As for Dolly the sheep, in all reference books her “father” is still considered to be Ian Wilmut, and not Kate Campbell...
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