A clearer distinction is needed between GMOs and organisms whose genome has been modified

Graphic abstract. Credit: DOI: 10.1016/j.tibtech.2021.11.001

Researchers from Hokkaido University have proposed a framework to aid in the demarcation between genetically modified organisms and genome-modified organisms, taking into account both scientific and socio-ethical considerations.

Producers have been breeding plants and animals for desired traits, including higher yields, better taste and flavor, and disease resistance for millennia. With the advent of DNA manipulation techniques in the 1970s, genetic recombination between different species became possible. Genetic recombination is used in the creation of genetically modified organisms (GMOs), such as plants and animals that contain genes from another species. Following more recent technical developments, genome-edited organisms (GEOs) – organisms whose genomes are modified more directly to achieve desired traits – have also been developed.

Megumi Ishii and Tetsuya Ishii from Hokkaido University’s Office of Health and Safety provided a detailed and clearer framework for distinguishing between agricultural GMOs and GEOs, with scientific, ethical and social considerations. Their work has been published in the journal Trends in biotechnology.

Introducing DNA from one species into another unrelated species (exogenous DNA) raises ethical concerns, including risks to human health and the environment. As a result, most countries have enacted laws that regulate the creation and use of GMOs. Currently, several countries, with the exception of Japan, have commercially grown GM crops for food; however, globally, only a few GM animals have been approved for food consumption.

Creating GEO with genome editing techniques, such as CRISPR/Cas9, involves more direct use of DNA-cutting enzymes in cells. Most genetically modified plants and animals are created without containing exogenous DNA, and therefore ethical concerns about exogenous DNA do not normally apply to them. From a legal standpoint, a handful of countries consider GMOs to be GMOs. On the other hand, several countries, including Argentina, Australia, Brazil, Chile, Colombia, Japan, and the United States, have regulations distinguishing between the two based on the existence of exogenous DNA; however, these regulators assess the non-existence of exogenous DNA in GEO on a case-by-case basis. Basically, genome editing could unintentionally cause genetic recombination if exogenous DNA is present at any part of the process.

The authors set out to provide a detailed framework that included both scientific, ethical and social considerations, to make a clearer distinction between the two. Even in countries where the legal distinction between the two already exists, this framework will strengthen the reliability of the relevant regulations.

Depending on the method used to create GEOs, they may contain exogenous DNA, which has a chance of integrating into the organism. Therefore, in the framework, if there is no exogenous DNA involved in the process, the resulting GEO can be safely considered distinct from a GMO.

However, if the reagents or culture medium contain exogenous DNA, the resulting GEO should be rigorously tested for the absence of exogenous DNA in the genome. This can be done by first determining the points in the genome where exogenous DNA is likely to be integrated. These regions are then analyzed by multiple complementary assays, such as target DNA sequencing, whole genome sequencing, and genomic Southern blots. If exogenous DNA is found, the GEO will be considered a GMO.

According to the authors, the proposed framework also requires ethical and social considerations before implementing large-scale policies to exempt GMOs from GMO regulations. A cost-benefit analysis, weighing the potential benefits of adopting a genetically modified crop or animal against the potential harm to humans, the environment, and animal welfare. Depending on the considerations, regulators can apply a simplified test to detect exogenous DNA. However, the final regulatory decision must be made based on informed public consultation and social consensus.

Pseudobulbs: exogenous nitrogen sinks in epiphytic orchids

More information:
Megumi Ishii et al, proving that an organism whose genome has been modified is not a GMO, Trends in biotechnology (2021). DOI: 10.1016/j.tibtech.2021.11.001

Provided by Hokkaido University

Quote: Clearer distinction needed between GMOs and genome-edited organisms (2022, Jan 24) Retrieved Jan 24, 2022 from https://phys.org/news/2022-01-clearer-distinction-gmos -genome-edited.html

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