Evidence that Genome Editing is Preferable to Transgenesis for Enhancing Animal Traits

Abstract Production traits such as growth, disease resistance, and fatty acid content in engineered animals are anticipated to be enhanced via transgenesis or genome editing. It is, however, unclear whether this expectation is upheld across taxa on a global comparison. Here, we perform a meta-analysis of 154 studies involving 72 species and 55 genes to quantify and compare the effects of transgenesis and gene editing on production traits in animals. While transgenesis is more commonly applied for trait enhancement, gene editing demonstrates more pronounced and widespread effects, particularly on growth and disease resistance traits, as reflected by larger effect sizes and broader impacts across trait responses. Yet, we observe taxon- and parameter-specific differences in patterns of trait enhancement. For instance, transgenesis reduces pathogen load in chickens and cattle but not in pigs, whereas gene editing lowers virus RNA levels in pigs but has limited success in chickens and cattle. In contrast, both transgenesis and gene editing significantly increase growth rates in ray-finned fishes. Notably, although transgenes or edited genes remain highly expressed or repressed in F 1 offspring, the magnitude of trait improvement is diminished compared to the founder generations. This study provides evidence-based insights that can assist researchers in refining their methods and directing future investigations into trait enhancement in genetically engineered animals, while also playing a key role in policymaking.