Gene editing: Breeding or GMO?

Abstract

Global regulatory frameworks will soon be challenged by recent scientific developments in methods for generating genetically modified animals, particularly gene editing techniques. It is unclear whether animals produced using such technologies will fall under or outside of the regulations developed for genetically engineered (GE) animals produced using recombinant DNA (rDNA) techniques. Many gene editing applications will result in animals that carry induced mutations in target genes or desirable alleles or sequences that originated in other breeds or individuals from within that species. As such, there will be no rDNA or transgenic construct in the animal, and no novel combination of genetic material that has been altered in a way that could not be achieved by natural mating or techniques used in traditional breeding and selection. The current regulatory approach to GE animals has had a stifling effect on the use of this technology in animal breeding programs, and to date no GE animal has yet been sold for food purposes anywhere in the world. Given the importance of improved genetics to the overall environmental footprint of food production, precluding breeder access to safe innovations for use in genetic improvement programs has a large opportunity cost. If genome editing is going to have an opportunity to impact global animal breeding programs its oversight should ideally be proportional to risk based on the novelty of the trait, consider and evaluate both benefits and risks, and fit for purpose, meaning that the reduction in risk obtained by regulatory oversight is greater than the costs of compliance.

Regulatory frameworks for genetically modified animals are concurrently being formulated in many countries in concert with rapidly advancing technologies for creating such animals including gene editing and approaches to generate targeted gene knockouts in livestock species. These new animal breeding techniques result in genetically modified organisms (GMOs) that do not fit the classic definition of “transgenic” or genetically engineered (GE), although they are produced through human intervention using recombinant DNA (rDNA) techniques. Some groups have argued that because these genetic modifications are, for at least part of the procedure, produced outside the organism by people using in vitro techniques this alone should be the trigger for regulation (1). However, this seems to disregard the plethora of in vitro techniques that are commonly utilized in conventional animal breeding programs (2). If risk is the main rationale for regulating genetic modification methods, there does not appear to be a clear rationale for regulating only traits and DNA sequences produced using rDNA techniques. If human intervention using in vitro techniques in breeding programs is the trigger for regulation, this would seem to apply equally to many of the breeding methods used in the production of modern broiler chickens and high-producing milk cows which are clearly genetically modified animals relative to their wild ancestors the jungle fowl and auroch, respectively.