Making an identical copy of any living substance or a cell is the simplest definition of cloning. And in the world where science is taking the globe by storms, cloning is undoubtedly a hot topic of discussion, which obliviously is not free of controversy. Moreover, this topic shines a light on the fundamental question “So is cloning even important?”.
Well, when you get a beautiful dog (for example, Siberian Husky) of such a high price, wouldn’t you be super happy if you could make another one just like her and keep it or sell it, as you wish? Hold up, I know this might not sound right, but cloning few endangered species, who are failing to reproduce can literally save the ecosystem from significant danger.
Additionally, this technology could even be used for cloning stem cells of a diseased person, so different types of research can be done on these cells. However, when it comes to cloning a full human being, this whole topic still gets controversial!
The process of producing genetically identical organisms or DNA fragments, by using somatic cells, either artificially or naturally is called cloning; moreover, many species in our ecosystem do cloning naturally ( examples- bacteria, fungi, and even blueberry plants, hazel trees).
Cloning, genuinely speaking, is not a new terminology in science as it dates back to 5000BC when humans first discovered that planting seeds in the soil could grow a new crop. However, the first successful artificial cloning was invented by Steen Willadsen in 1984, and I’m sure you have heard of the famous lamb, Dolly, which was created by no other than Mr. Willadsen.
However, a scientific idea of cloning from a somatic cell came from a German scientist Hans Spemann, in 1938, when he proposed a “fantastical experiment” to transfer one cell’s nucleus into an egg without a core nucleus, whose primary method was eventually used in cloning. Hans Spemann used salamander eggs for his experiments, and the first nuclear transfer experiment was also done in salamander embryos. Similarly, In 1944, Oswald Avery discovered that genetic information is carried by the nucleic acids of cells, which became a foundation for Watson and Crick to discover the structure of DNA in 1953.
Timeline of Cloning
|1958||F.C. Steward grew whole carrot plants from carrot root cells, which encouraged the belief that cloning from adult cells may be possible.|
|1962||John Gurdon cloned frogs from differentiated adult cells.|
|1966||Niremberg, Mathaei, and Ochoa determined which codon sequences specify each of the 20 amino acids, thereby “cracking the genetic code” and opening the door to advances in genetic engineering.|
|1969||Shapiero and Beckwith isolated the first gene.|
|1972||Paul Berg created the first recombinant DNA molecules.|
|1973||Cohen and Boyer created the first recombinant DNA organisms.|
|1977||Fred Sanger invented a method for sequencing DNA, which later enabled researchers to map the genomes of various species.|
|1983||Kary B. Mullis developed the polymerase chain reaction technique for rapid DNA synthesis|
|1984||Steen Willadsen, a Danish scientist, reported he had made a genetic copy of a lamb from early sheep embryo cells, a process now called twinning. This process is the first verified cloning of a mammal via nuclear transfer. Other scientists would eventually use his method to twin cattle, pigs, goats, rabbits, and rhesus monkeys.|
|1986||Steen Willadsen cloned cattle from differentiated cells.|
|1990||Human Genome Project began|
|1994||Neal First produced genetic copies of calves from embryos. They grew to at least 120 cells.|
|1996||Dolly, the first animal cloned from adult cells, was born (not announced until 1997).|
|1997||1. Only a week after the Dolly announcement, scientists brought cloning technology closer to humans by twinning rhesus monkeys from embryos.
2. The first cloned cow was produced from a fetal cell.
3. Researchers at the University of Hawaii produced the first mouse cloned from an adult cell.
4. The scientists who produced Dolly announce that they had created a lamb with a human gene in every cell of its body. Named Polly, the lamb was produced using a method similar to that used to create Dolly.
5. Richard Seed, a successful fertility researcher, announced his plans to clone a human.
|1998||Ryuzo Yanagimachi and his postdoctoral student Teruhiko Wakayama in Hawaii cloned some 50 mice from an adult cell. Some of the mice were cloned of clones, created by using a technique different than that used to produce Dolly the sheep. The first project aimed at cloning a domestic pet, a dog named Missy (Missyplicity Project), was launched.|
|1999||Researchers at the University of Hawaii produced Fibro, the first male clone. The mouse was named after the type of cell—a fibroblast or connective tissue cell—that was taken from the genetic donor. All previous clones of adult mammals had been female.|
|2000||1. Britain became the first country to grant a patent for cloned early-stage human embryos. Geron Corporation, which received the patent, said it has no intention of creating cloned humans.
2. The group that created Dolly the sheep announced the first cloned pigs. Scientists hope that pigs could be genetically engineered for use in human organ transplants.
|2001||1. An endangered Asian ox called a gaur was cloned. It died two days after the birth of an ordinary disease after it was cloned and gestated in the womb of a cow.
2. The first human clone embryo was produced; it was planned for embryonic stem cell harvesting, not reproductive cloning. However, it stopped dividing before stem cells can be harvested
|2002||The first rabbits are cloned from adult cells.|
|2003||The first cloned bantengs (endangered species) were born to cows. The genetic donor had died 23 years earlier and his DNA preserved in the “Frozen Zoo” at San Diego Zoo’s Center for the Reproduction of Endangered Species.
The first horse was cloned from an adult cell. The first deer was cloned from an adult cell. The first African wildcat was cloned from an adult cell.
|2004||The first domestic cats were cloned using CT technology and publicly displayed.|
|2005||1. Researchers at Seoul National University produced Snuppy, the first clone of a domestic dog.
2. Unrelated cloned African wildcats were successfully bred under natural conditions. This was the first time unrelated clones of a wild species had produced offspring.
Everything has its pros and cons. Thus, if cloning is done correctly for medical purposes and the betterment of not only humanity but the whole ecosystem in general, the results will surely be beneficial. Nevertheless, if cloning is used for selfish purposes and to make duplicate humans for experiments, then it surely will create great problems that could be beyond our imagination. Therefore, cloning is a beautiful technique with lots of progress over time, but if not used well, it might lead to the destruction of humankind.
References: National Science Teaching Association | Reproductive Cloning