Gene editing in livestock: promise, prospects and policy.

Abstract

Abstract Although genetically engineered livestock were first introduced in the 1980s, only three biomedical applications (ATryn®, Ruconest®, Kanuma®) and one food animal application (AquAdvantage® salmon) have been brought to market. The initial promise of this technology was hampered by low efficiency, random site integration, public resistance and regulatory hurdles. Gene editing has made it possible to precisely target changes in livestock genomes, overcoming previous challenges. Livestock and poultry editing applications include disease resistance, animal welfare, production traits, animals as bioreactors, xenotransplantation and the development of models for human diseases. The extent to which any of these applications are utilized beyond research laboratories will depend upon regulatory frameworks, uptake by livestock producers and industry, and public acceptance. The 2017 draft US Food and Drug Administration regulatory guidance for gene edited animals, which proposes to regulate 'intentional' genomic alterations introduced by editing as new animal drugs irrespective of product novelty or risk, is at odds with emerging regulations around gene edited plants. Lengthy process-based regulation triggered by human 'intention' rather than novel product risk may dissuade animal genetics companies and breeders from employing gene editing to introduce beneficial genetic alterations into livestock populations, effectively the same fate encountered by genetic engineering in animals. Goal conflicts will likely continue between genetic innovations to address problems like animal disease and welfare and concerns around the use of modern molecular genetics in food animals. The early applications that successfully navigate regulatory hurdles will influence the public discussion around gene edited animals and impact the trajectory of future applications.