The purpose of genetically modified muscle pig industry is very prominent.

?? When you talk about "pork belly", you must think of pigs, but have you ever thought that maybe one day the pork belly will disappear from pigs? Jin Zhenxiu, a molecular biologist at Seoul University in South Korea, and his colleagues used targeted gene knockout technology "Talen" to remove muscle growth suppressor genes from pigs, and then implanted these modified genes into pig embryonic cells, allowing sows to give birth to 32 piglets. The muscle cells of these piglets will grow without restriction and become "muscle pigs" instead of growing into a chubby figure like their peers. Eight months later, 13 piglets survived, while only two remain, only one of which has been assessed as "healthy". Jin Zhenxiu said that in the past, it took people decades to cultivate a new animal breed, but with the help of genetic technology, it can be done in a relatively short time. However, the researchers have no plans to introduce "muscle pigs" into people's daily diet. At present, many countries stipulate that the sale of GM meat is not allowed because it is not clear about the impact of genetically modified meat on the environment and human health.

According to the website of Yanbian University in Jilin Province, China, this achievement was completed by Professor Yin Xijun of Yanbian University in Jilin Province of China in cooperation with the Jin-Soo Kim team of Seoul National University in South Korea. The school's official website published a report:

A few days ago, Nature/news reported on the research results of Professor Yin Xijun's team at Yanbian University, entitled "Super-muscly pigs created by small genetic tweak" (production of super lean pigs through small-scale genetic modification, Nature 52313-1402 July 2015 doi:10.1038/523013a). This innovative achievement is accomplished by the research group of Professor Yin Xijun of our university and the Jin-Soo Kim team of Seoul National University. Nature magazine is one of the most influential academic journals in the world. The published paper represents the substantial progress of an important scientific issue and has an important short-term and long-term impact. This is the first scientific research achievement reported by our university on Nature News.

Belgian blue cattle is the leading breed of Belgian beef cattle, which has developed into a "bodybuilding cow" with double muscle genes, strong muscles and strong physique after decades of cultivation, Nature reported. The research team used a new generation of genome editing technology and somatic nuclear transfer technology to simulate the natural mutation of muscle growth inhibin gene (Myostatin,MSTN) in large animals without the introduction of exogenous DNA sequences, and obtained bimuscular boars, all of which showed muscle overexpression characteristics. This kind of bicuspid pigs may become the first batch of genetically modified animals to be approved for human consumption.

MSTN is a negative regulator of skeletal muscle growth and development. The loss of its activity is characterized by the "double muscle" character of animals. Mutations of MSTN gene have been found in cattle, sheep, dogs, humans and so on. Among them, mutant cattle have been selected into a new breed of beef cattle, which has been introduced as the terminal male parent of cross improvement by dozens of countries in the world. The beef has soft meat, low fat and cholesterol content and high protein content. Known as "heart beneficial beef", it is very popular among consumers in Europe and the United States. However, pigs with MSTN gene mutations have not been found in nature. In order to introduce MSTN mutation, the research team used TALEN gene editing technology to construct a fusion protein with endonuclease and break the target gene DNA sequence at a specific site, so that DNA editing and modification operations can be carried out at this site, such as knock-out, knock-in, base substitution, point mutation or gene modification.

The research team designed and constructed plasmids that can knock out MSTN gene efficiently and transferred porcine fetal fibroblasts by electrotransfection. Positive cells were selected by magnetic beads as donor cells, and somatic cell nuclear transfer was performed after chemical-assisted enucleation. After the pregnancy was confirmed by embryo transfer, the fetus was taken out for gene sequencing, and the MSTN bilateral knockout fetal cells were used as donor cells for somatic nuclear transfer, and 32 bi-muscular pigs were obtained (of which 13 survived to 8 months). In this study, the construction of gene knockout plasmid and gene sequencing were carried out by Pro. Kim team, Professor Yin Xijun of Yanbian University is responsible for gene transfection, somatic cloning and production and management of cloned animals.

Heiner Niemann, a senior researcher in the field of gene editing tools at the Friedrich Loeffle Institute in Germany, said the pig showed typical bimuscular traits, characterized by well-developed muscles in the back and buttocks.

Professor Yin Xijun said that although the produced double-muscle pigs have a series of common management problems in other animals with double-muscle traits, such as dystocia and low survival rate of piglets, they can be used to establish a new concept of lean meat breeds. improve lean meat rate, meat quality and economic benefits to achieve the goal of industrialization.

The new generation of gene editing should be regarded as a new technology developed on the basis of traditional mutation breeding, which is more comparable to the traditional mutation breeding technology in terms of safety-both of them are essentially equivalent to artificial mutation technology. only accelerate the process of natural mutation. This new breeding technique has higher accuracy and shorter cycle than traditional mutation breeding. Because this new technology can not rely on the introduction of exogenous DNA sequences, the genetically modified biomaterials obtained by this technique are actually not essentially different from all kinds of natural polymorphic individuals formed by long-term evolution in nature. At present, the US government has approved the first plant material obtained by genome directed modification in 2012, which can be directly used as a conventional variety for field evaluation.

Dr. Kang Jindan is the main researcher in charge of the project by Professor Yin Xijun's team and is one of the main adults of the research results.

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