Is Gene Editing safe? There is a confrontation between the pros and cons of the international seminar, and the attitude of the traditional breeders is reserved.

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This year's Nobel Prize in Chemistry was awarded to two female scientists in the United States and France who studied the "gene editing" (Gene Editing) technology, but there are many disputes about this technology in medical treatment, and scholars in various countries have different views on agricultural applications. Last week (October 13), the international symposium on crop precision breeding was unveiled at Zhongxing University, where scholars from all over the world clashed with each other.

Some scholars attending the meeting believe that the gene editing technology (SDN1), which destroys some gene fragments and allows the genes to repair and produce mutations by themselves, does not insert foreign genes, which is no different from traditional breeding, and can even increase the efficiency of traditional breeding, and should not be regarded as genetic modification.

Scholars who do not agree with gene editing believe that gene editing will have a "miss effect", meaning that non-target gene fragments may also be changed, which may have unforeseen side effects. At the meeting, some British scholars pointed out that chromosome confusion and protein abnormalities have appeared in many experiments and literature, and gene interference may produce toxins and allergens, so it is impossible to prove that gene editing is safe.

Zhou Guolong, director of the south branch of Kaohsiung Agricultural Reform Farm, who is known as "Mr. Dou", believes that according to the literature, the lack of exogenous gene editing technology can indeed shorten the breeding time. "the technology itself is neutral, and whether there is controversy depends on the original intention of the users, whether they want 'Feeding the world'?." Or is there something else? "

International Symposium on crop Precision breeding (Photography / Lin Yijun) Gene editing has no foreign genes, interrupting gene fragments to repair themselves

Since Mendel, the "father of genetics", scientists have improved crops through cross breeding. After the emergence of DNA sequencing in the 1960s, modern breeding techniques developed vigorously, in which gene modification and gene editing techniques caused a lot of controversy.

Hung Chuan-yang, a professor in the Department of Agricultural Chemistry at National Taiwan University, explains that breeding produces genetic variation through repeated hybridization of crops, screening traits that meet people's needs, such as different colors, fruit weight, and plant height. However, because naturally induced genetic variation requires a large number of hybrid samples, and the probability of occurrence is low, physical (Gamma-ray), chemical (EMS) or biological mutagenesis are used in traditional breeding.

With regard to the differences in gene editing and genetic modification technology, Hong Chuanyang explains that genetic modification is commonly known as "transgene", which is based on the principle of interrupting the gene and inserting foreign genes that meet the needs (Note 1). The crop will repair itself, and when it is repaired, it will produce mutations, but it is still the genes of the same kind of organisms and can continue to reproduce.

Hong Chuanyang said that the disadvantage of traditional breeding is that it is not accurate enough, for example, rice that produces disease-resistant varieties has become unpalatable. In addition, traditional breeding requires repeated backcross (Note 2), some crops grow for a long time, breeding is time-consuming, and the emergence of gene editing is to make breeding techniques more accurate and improve efficiency.

Differences between gene editing (SDN1) and gene modification (SDN2 and SDN3) (data source / Hong Chuanyang) is the gene editing technique accurate? Whether the "off-target effect" can be overcome is still controversial in academic circles.

Scholars and civil society who do not agree with genetic editing and genetic modification believe that the food risk of crops produced by these technologies has not been assessed, and that these technologies have a "off-target effect", meaning that non-target gene fragments may also be changed. may have unforeseen side effects.

For example, the US company Recombinetics bred non-horned cattle with gene editing technology in 2016. Although there are no foreign genes, US officials have found that non-horned cattle carry three antibiotic genes from bacteria.

With regard to the query about the off-target effect, Hong Chuanyang said that the results of the application of gene editing to animals and plants are different. If an animal has a gene deletion, it may lose an eye or a leg, but in the process of plant breeding, a large number of variations are needed for selection, and if the off-target effect produces non-target traits, it can be eliminated.

But Michael Antoniou, a professor in the Department of Molecular Genetics at King's College London, questioned, "if it's as safe as natural mutations, why apply for a patent?" Many supporters of gene editing believe that the off-target effect is not harmful as long as it is accurately controlled, but in fact, large genetic changes will affect the function of other genes, and chromosome confusion and protein abnormalities have appeared in many experiments and literature.

Michael Antoniou believes that the chemical interaction in biological genes is quite complex. Take "hornless cattle" as an example, genetic interference may also produce toxins and allergens. At present, it is impossible to prove that gene editing is safe.

Michael Antoniou (Photography / Lin Yijun), a professor in the Department of Molecular Genetics at King's College London, UK, believes that different countries regard it as a fundamental change in the European Union and a non-fundamental reform in the United States, Japan and Australia.

The crops cultivated by gene editing technology are mainly rice, tomato, corn, wheat, soybean, cotton and citrus crops, but is it safe for the public to eat gene editing crops?

At present, officials in the United States, Japan, Australia and other countries have regarded gene editing crops and products as non-genetic modification, but the European Union still believes that gene editing belongs to genetic modification. During the seminar, scholars from the United States, Australia, Japan and Europe were invited to explain the current situation of various countries online.

Yutaka Tabei, director of the extension office of the Agricultural and Food Industry Technology Comprehensive Research Institute of the Japanese National Research and Development Corporation, said