On the 19th of this month, the first commercial cloned cat in China was officially announced
The cloned cat, named "garlic", was born on July 21 this year
Identified as a cloned cat by a third-party organization, "garlic" is also the first fully self bred cloned cat in China
It is understood that Huang Yu, the owner of the cloned cat "garlic", chose cloning technology to restart his new life in memory of his dead pet cat
The cloned cat was born on July 21 after natural birth of a surrogate cat
Is the cloned cat "garlic" the same as the deceased pet cat? Why does the hair color change? The weekly reporter interviewed experts from Jiangsu Key Laboratory of xenotransplantation to reveal the story behind cloning
Clonal cat "garlic" clonal definition: asexual reproduction of organisms in 1963, holdan, a group geneticist, first put forward the term "cloning" in a speech entitled "biological possibility of human race in the next 20000 years"
In 1997, the news that a sheep named Dolly was born through cloning technology immediately attracted worldwide attention
Since then, cloning has become a hot topic
Clone is a transliteration of the English word clone
Its original meaning means that seedlings and twigs cultivate plants by asexual or vegetative propagation
With the passage of time, the connotation of cloning has expanded
It generally refers to the asexual reproduction of organisms through somatic cells and the population composed of offspring individuals with exactly the same genotype formed by asexual reproduction; It usually uses biotechnology to produce individuals or populations with exactly the same genes as the original individuals by asexual reproduction
In fact, cloning is no stranger to us
We often use this biological method of asexual reproduction in our daily life
For example, when flowers bloom in spring, people who like to plant flowers and grass will do plant cutting experiments
From a plant, cut branches, through cutting, you will get many plants with the same genetic material, which is cloning
Asexual reproduction is more common in lower organisms
The division and reproduction of bacteria and planarians is that their parents split vertically or horizontally into two daughters, and then separated from their parents to become independent individuals, which also belongs to cloning
But does asexual reproduction exist in higher organisms? Scientists once believed that it was impossible for a mature somatic cell to reproduce asexually to become a complete animal
Although an individual cell contains complete genetic information about an animal, the somatic cell has been specialized
Generally speaking, liver cells can only produce liver tissue, and breast cells can only produce breast tissue
The birth of Dolly sheep has completely changed people's understanding, creating a precedent that higher animals can also be cloned
"First, the nucleus of the donor cell containing genetic material is transferred to the egg cell with the nucleus removed, and the two are integrated by micro current stimulation, and then the new cell is promoted to divide and reproduce and develop into an embryo
When the embryo develops to a certain extent, it is implanted into the uterus of the surrogate animal to make the animal pregnant, and then an animal with the same gene as the nuclear provider can be born
" Lirongfeng, researcher of Jiangsu Key Laboratory of xenotransplantation, introduced the cloning process of higher organisms
She said that the cloning technology does not require male and female mating, nor does it require the combination of sperm and eggs
It only needs to extract a single cell from an animal, artificially cultivate it into an embryo, and then implant the embryo into a female animal to give birth to a new individual
The cloned animals cultured in single cells have exactly the same characteristics as single cell donors and are "replicas" of single cell donors
British scientists in England and American scientists in Oregon have successively cultivated dolly, a "cloned sheep", and a "cloned monkey"
Chinese scientists have also gradually cultivated "cloned cattle", "cloned rabbits", "cloned pigs" and currently updated "cloned cats"
Wonderful cloning technology has shown broad application prospects, such as cultivating excellent animal breeds and producing experimental animals, producing transgenic animals, producing human embryonic stem cells for cell and tissue replacement therapy, replicating endangered animal species, preserving and disseminating animal species resources, and maintaining ecological balance
Four surrogate cat mothers produced a cloned cat
On January 9 this year, Huang Yu, the owner of the deceased pet cat, formally proposed to Beijing sinovalley Biotechnology Co
, Ltd
to clone "garlic" because he missed it too much
After the scientific research and technical team explored the conditions for in vitro maturation culture of oocytes, parthenogenetic activation and other pre experiments, the research and development experiment of cloned cats was officially started in August, 2018, and 152 experiments were conducted
Up to now, one surrogate cat has successfully given birth, and one surrogate cat has been tested to be pregnant and ready to give birth
In the "garlic" cloning cat project, a total of 4 surrogate cats were transferred by embryo transfer
Among them, the surrogate cat cntr258 gave birth naturally on July 21, 2019 after 66 days of embryo transfer
The cloned cat "garlic" was a very cute British short haired cat
The basic principle of the body cat "garlic" is the same as that of cloning sheep and pigs
After obtaining the oocytes of the surrogate cat, we knock out and enucleate the surrogate cat's genes, and then implant them into the cells of the cloned cat to form a fusion cloned embryo for activation Wangyining, deputy general manager of Beijing sinovalley Biotechnology Co
, Ltd
, introduced the birth process of the cloned cat "garlic"
"Judging from the current level of cloning technology, from the pregnancy of four surrogate cats and the successful birth of a cloned cat, the profit rate is high
" Chendayuan, a researcher at the Institute of zoology of the Chinese Academy of Sciences, said
Lirongfeng also said that as a new species, the fertility rate of 25% is very high
Taking the cloned pigs in Jiangsu Provincial Key Laboratory of xenotransplantation as an example, at present, one to three transgenic cloned pigs can be obtained after 100 embryos are transplanted, and the cloning efficiency is about 3%
Shizhensheng, a professor at the school of animal medicine of China Agricultural University, introduced: "the reproductive physiological characteristics of cats are different from most animals, because cats are not spontaneous ovulating animals, but one of the few animals that induce ovulation
Their reproductive cycle is special, cloning technology is difficult, and the operation is cumbersome
This successful breeding of cloned cats is one of the few successful cases in the world, marking a big step forward in the field of cloning in China
" "For the public, it may be incomprehensible to spend 250000 yuan to clone a cat
But when they knew that the cloning price was 250000 yuan, they were still very happy
" Huang Yu, the owner of "garlic", said that he had searched the Internet
There was a cloning agency in South Korea that cloned cats and dogs at a price of fourorfive million, which was relatively expensive; The price of 250000 yuan for domestic cloned cats is acceptable
It can provide reference for cloning pandas
On August 21, the cloned cat "garlic" had a full moon
From the photos of "garlic" published on the Internet, it can be found that there is a slight difference between the cloned "garlic" and the body "garlic": there is a small black block on the chin of the body, but the cloned cat does not; There is a pattern on the left leg of the body, and the clone cat pattern is on the right leg
"There is an epigenetic problem in the process of animal cloning
The so-called epigenetic problem is that environmental factors will lead to different gene expression, but the gene itself will not change
" Lirongfeng explained that the genes in the cloned cat's gene nucleus are the same as the original genes derived from the cat's cells, but there will be differences in gene expression in the process of reprogramming the somatic cells
The genes are inherited from the genes of the previous cat, but some genes are not expressed or overexpressed; In the cloned cat "garlic", the expression of hair color related genes is incorrect
Beijing sinovalley Biotechnology Co
, Ltd
also responded: "cloning ensures that more than 99
9% of the genes are the same, but there is randomness in the expression of hair genes
There are patterns on the body, so it is impossible to ensure that 99
99% of the genes are the same
"
At the same time, Beijing sinovalley Biotechnology Co
, Ltd
also pointed out that cloned cats can not guarantee the same living conditions and breeding environment as the body, and their personalities may change
So what might happen to your personality? Lirongfeng said that there are many acquired factors in the formation of the character of cloned cats, just as the character of human twins will be different in different environments; But there are some basic personality determining genes
If they exist in the nucleus, even if the environment is different, the personality will not change greatly
What is the significance of the birth of the cloned cat "garlic"? Lirongfeng said that from the economic point of view, it is not as significant as meat animals, but it caters to the emotional needs of some people, such as pet owners, and can play a role of companionship
"Another great significance lies in the cloning of cats, which are close to giant pandas in species compared with pigs and dogs
" Lirongfeng said that the giant panda is a rare and endangered species, which is difficult to clone
The successful cloning of cats can provide a reference for the cloning of rare and endangered species such as the giant panda
Intersection reporter Zhang Xuan
