A comprehensive meta-analysis published in Engineering in 2026 offers systematic quantitative comparisons between transgenesis (TG) and genome editing (GE) in boosting farm animal production traits, identifying consistent performance gaps between the two mainstream genetic modification tools. The research team integrated datasets from 154 peer-reviewed controlled experiments covering 72 animal species and 55 functional genes, building a database with 1145 standardized mean difference (SMD) effect sizes to evaluate outcomes in growth, disease resistance and fatty acid composition across taxa.

Developed in the 1980s, transgenesis randomly inserts foreign DNA into host genomes, while genome editing tools including CRISPR/Cas9, TALENs and ZFNs enable targeted gene knockouts or knock-ins at specific genomic loci. The paper confirms transgenesis has been deployed more widely in existing research, yet genome editing delivers larger effect sizes and broader beneficial impacts on growth and disease resistance overall. Species-specific trait responses differ distinctly between the two technologies: transgenesis cuts pathogen load in chickens and cattle without equivalent effects in pigs, whereas genome editing suppresses viral RNA concentration in pigs but yields weaker protective effects in poultry and bovine livestock. Ray-finned fish display consistent growth acceleration under both genetic manipulation approaches.

Both technologies alter target gene expression in predictable patterns: transgenesis drives significant upregulation of exogenous genes, while genome editing suppresses transcription of endogenous target genes, with expression levels shaped by species, gene type and tissue location. For growth traits, genome editing generates a larger pooled SMD effect size than transgenesis, producing measurable improvements in body weight, specific growth rate, muscle fiber quantity and dimension across cattle, fish, goats, pigs and sheep, though its growth-modifying effect lacks statistical significance in chickens. Myostatin, mc4r and IGF2 are validated as high-impact candidate genes for growth-focused editing.

No unified significant overall effect on disease resistance was detected for combined TG and GE datasets due to divergent parameter outcomes. Transgenesis elevates cumulative survival rate and lowers pathogen load, viral RNA and viral titer in targeted taxa, while genome editing notably reduces viral RNA and viral titer and improves post-infection survival in pigs via modification of CD163 and PCBP1 genes. Modifications targeting fatty acid profiles show high heterogeneity across species and genes; transgenesis generates meaningful rises in DHA concentrations and reduced ω-6/ω-3 ratios, while available genome editing fatty acid data is limited to a single chicken study with non-significant phenotypic shifts.

The analysis also documents two universal trends across all trait categories. First, trait enhancement magnitude declines with animal age, observable in specific growth rate, muscle fiber metrics and polyunsaturated fatty acid profiles. Second, though transgenes and edited genes maintain stable expression or repression in F1 progeny, the scale of trait improvement weakens relative to founder P1 individuals, likely linked to heterozygosity and incomplete penetrance. The research team completed publication bias assessment and leave-one-out sensitivity testing to verify dataset stability, stating the findings deliver evidence-based references for laboratory method optimization and regulatory policy formulation for genetically engineered livestock and aquaculture species.

The paper “Evidence that Genome Editing is Preferable to Transgenesis for Enhancing Animal Traits,” is authored by Jinhai Wang, Shinichi Nakagawa, Jiaqi Wang, Robert Stewart, Alexandra Florea, Rex A. Dunham, Fei Ling, Gaoxue Wang, Lily Liu, Diego Robledo. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.11.032. For more information about Engineering, visit the website at https://www.sciencedirect.com/journal/engineering.