Gene Editing: Potential and Perceptions

A new report from the Council for Agricultural Science and Technology (CAST) offers a primer on the science of genome editing, along with potential applications and challenges.

Back in the 1860s, Gregor Mendel first described the principles of genetic inheritance. Much earlier though, farmers engaged in genetic selection by saving seeds from their strongest, healthiest plants. They didn’t know how it worked, but they correctly believed they could improve subsequent generations of their crops. The process was slow, and results were unpredictable, but over the past century, plant and animal breeders learned to apply Mendel’s principles toward genetic progress.

Using conventional selection for a particular desirable trait often brings along some baggage in the form of undesirable traits. And conventional breeding still takes considerable time, often several years, to generate commercially viable improvements. Genetic engineering, typically using foreign DNA to introduce novel traits, has complemented conventional breeding in recent years. Many consumers though, remain skeptical of these genetically modified organisms (GMOs) in the food supply.

Genome editing is a different beast altogether. According to the CAST report, genome editing is the process of making precise, targeted sequence changes in the DNA of living cells and organisms. Recent advances have made genome editing widely applicable, offering the opportunity to rapidly advance basic and applied biology.

Genome editing can, with a high level of precision, create genetic change in months, rather than the years to achieve similar results using conventional selection methods.

The CAST report describes how genome editing is performed, the types of “edits” that can be made, how the process relates to traditional breeding and conventional genetic engineering, and the potential limitations of the approach. The paper also explores governance of genome editing, including existing regulations, international agreements, and standards and codes of conduct.

Key points in the report include:

• Genome editing, as it is most frequently practiced, uses reagents that specifically recognize and precisely cleave DNA targets within the genomes of living cells.
• Genome editing has potential to have a large, positive impact on plant agriculture, due to efficiency and because it causes relatively few or no mutations at unintended sites in the genome.
• Research indicates genome editing can improve production traits and health in livestock.
• The new technology has accelerated the development of improved crop varieties and livestock with commercial potential, making clarity in how they should be governed paramount.
• No method of genetic modification, including conventional plant or animal breeding, is without the possibility of unintended effects.
• Genome editing is likely to be subject to the same underlying factors of information processing and risk perception by individuals that have been found across multiple other emerging technologies.
• The power of genome editing suggests that, if conducive social and regulatory conditions are in place, it can substantially increase the positive impacts of plant and animal breeding on human welfare and sustainability.
• U.S. Secretary of Agriculture Sonny Perdue issued a definitive statement that the USDA “does not regulate or have plans to regulate plants that could otherwise have been developed through traditional breeding techniques as long as they are not plant pests or developed using plant pests.”
• Successful deployment of genome editing for crop and livestock improvement will benefit from science-informed, value attentive regulation that promotes both innovation and transparency.

The full CAST report, titled “Genome Editing in Agriculture: Methods, Applications, and Governance,” is available online.