It is the transliteration of the English word "clone". In Taiwan, Hong Kong and Macao, it is generally translated as replication or transproduction. It is a process of using biotechnology to produce offspring with the same genome as the original individual through asexual reproduction. Scientists The process of artificial genetic manipulation of animal reproduction is called cloning. This biotechnology is called cloning technology, which itself means asexual reproduction, that is, a pure cell line formed by the division and reproduction of the same ancestor cell. Each cell in the cell line has Genes are identical to each other.
The English word ‘clone’ comes from the Greek ‘klōn’ (twig). In horticulture, the word 'clon' continued to be used into the 20th century. Later an 'e' was sometimes added to the end of the word to become 'clone' to indicate that the 'o' was pronounced as a long vowel. Recently, with the widespread use of this concept and word in public life, the spelling has been restricted to the use of 'clone'. The Chinese translation of the word is transliterated as "clone" in mainland China, while in Hong Kong and Taiwan, it is mostly translated as "transplantation" or "copying". The former "clone" is like the transliteration of copy "copy", which has the disadvantage that it cannot be understood literally; while the latter "copy" can roughly express the meaning of clone, but it is inaccurate and prone to misunderstanding.
Cloning is usually an artificially induced asexual reproduction method or a natural asexual reproduction method (such as plants). A clone is a multicellular organism that is genetically identical to another organism. Cloning can be natural, such as by asexual reproduction or by chance, producing two genetically identical individuals (like identical twins). But what we usually mean by clone is an identical copy produced through conscious design.
Cloning technology is called "biological amplification technology" in modern biology. It has gone through three stages of development: the first stage is microbial cloning, that is, one bacterium is used to quickly replicate thousands of Tens of thousands of bacteria that are exactly the same as it become a bacterial group; the second period is biotechnology cloning, such as using genetic genes-DNA cloning; the third period is animal cloning, that is, cloning a cell into an animal . The cloned sheep "Dolly" was cloned from the somatic cells of a ewe using animal cloning technology.
In biology, cloning is usually used in two ways: cloning a gene or cloning a species. Cloning a gene refers to obtaining a piece of gene from an individual (for example, by PCR), and then inserting it into it. There is also asexual reproduction in the animal kingdom, but it is more common in invertebrates, such as fission reproduction of protozoa and urochordates. budding reproduction, etc. However, for advanced animals, under natural conditions, they can generally only reproduce sexually. Therefore, in order to reproduce asexually, scientists must go through a series of complex operating procedures. In the 1950s, scientists successfully reproduced an amphibian, Xenopus laevis, asexually, opening a new chapter in cell biology.
In the late 1980s, countries such as the United Kingdom and my country used embryonic cells as donors to "clone" mammals. By the mid-1990s, my country had used this method to "clone" five mammals: mice, rabbits, goats, cows, and pigs.
On the 19th, a lamb "Dolly" with the same genetic structure as the donor was grown, and the world's public opinion was in an uproar. The special thing about "Dolly" is that its life There is no sperm involved in the birth. The researchers first sucked out the genetic material from a sheep egg cell and turned it into an empty shell. Then they took out a mammary gland cell from a 6-year-old ewe and injected the genetic material into the egg cell. In this way, an unfertilized egg cell containing new genetic material is obtained. This modified egg cell divides and multiplies to form an embryo, which is then implanted into the uterus of another ewe. After a successful delivery, "Dolly" came to the world.
But why did other cloned animals not have such a big impact on the world? This is because the genes of other cloned animals come from embryos. Nuclear transfer using embryonic cells cannot be strictly regarded as "asexual reproduction". Another reason is that the embryonic cells themselves are sexually reproduced, and half of the genome in the nucleus comes from the maternal parent. The genome of "Dolly" all comes from a single parent, which is true asexual reproduction. Therefore, strictly speaking, "Dolly" is the first truly cloned mammal in the world. Its characteristic is that it is similar to It provides genetic material. On February 23, 1997, scientists from the Roslin Institute in Scotland, England, announced that their research team used goat somatic cells to successfully "cloning technology. It is the result of scientific development and it has extremely broad application prospects." . In horticulture and animal husbandry, cloning technology is an ideal means of breeding genetically stable varieties, through which high-quality fruit trees and improved livestock can be cultivated. In the medical field, countries such as the United States and Switzerland are currently able to use "cloning" technology to cultivate human skin for skin grafting surgeries. This new achievement avoids possible rejection reactions of allogeneic transplants and brings good news to patients. According to a report by China's Xinhua News Agency on April 4, 1997, Cao Yilin, an expert in plastic surgery at Shanghai Ninth People's Hospital, used the method of in vitro cell reproduction for the first time in the world to successfully replicate human ears on white mice, paving the way for the repair and maintenance of missing organs in the human body. Reconstruction brings hope.
Cloning technology can also be used to reproduce many valuable genes in large quantities, such as insulin to treat diabetes, growth hormone that is expected to make dwarfism patients grow taller again, and interferon that can resist various diseases and infections, etc.
Cloning is a major technological breakthrough made by mankind in the field of biological sciences, reflecting the progress of cell nuclear differentiation technology, cell culture and control technology. Originally the transliteration of English clone, it means a population of offspring individuals with identical genotypes formed through asexual reproduction of organisms, referred to as "asexual reproduction". Major breakthroughs in animal cloning technology have also brought widespread controversy.
The term "cloning" was introduced into horticulture in 1903, and was later gradually used in botany, zoology and medicine. "Clone" in a broad sense is actually something we often encounter in our daily lives, but we just don't call it "clone". In nature, there are many plants with innate cloning instinct, such as sweet potatoes, potatoes, roses and other plants propagated by cuttings. Animal cloning technology has experienced the development process from embryonic cells to somatic cells.
The 6-year-old ewe in the spring has exactly the same genes and can be said to be a copy of its mother. It is worth noting that while cloning technology brings huge benefits to mankind, it will also bring disasters and problems to mankind. However, we cannot prevent the development of this technology because it may bring serious consequences. Its emergence is ultimately more beneficial than harmful. It will be widely used to benefit mankind. An individual (usually through a vector) for study or use. Cloning sometimes refers to the successful identification of a certain -{A|zh-cn:phenotype;zh-tw:dominant}-gene. So when a biologist says that the gene for a certain disease has been successfully cloned, it means that the location and DNA sequence of the gene have been determined. Obtaining a copy of the gene can be considered a by-product of identifying the gene.
Cloning an organism means creating a new organism that has exactly the same genetic information as the original organism. In the context of modern biology, this often involves somatic cell nuclear transfer. In somatic cell nuclear transfer, the oocyte nucleus is removed and replaced with a nucleus from a cell in the organism being cloned. Usually the oocyte and the nucleus into which it is transplanted should be from the same species. Because the nucleus contains nearly all of life's genetic information, the host oocyte will develop into an organism that is genetically identical to the nuclear donor. Although mitochondrial DNA has not been transplanted here, there is still relatively little mitochondrial DNA, and its impact on organisms can usually be ignored.
Clone in horticulture refers to the offspring of a single plant produced through vegetative reproduction. Many plants obtain a large number of offspring from a single plant through asexual reproduction such as cloning.
The use of cloning technology can rescue rare and endangered animals, expand the population of well-bred animals, provide sufficient experimental animals, promote research on genetically modified animals, overcome genetic diseases, develop high-level new drugs, and produce organs for human transplantation It plays a role in the research of organs, etc., but if it is applied to human reproduction, it will cause a huge ethical crisis