- Genome editing is an advanced biotechnology that offers new opportunities to improve disease resistance in animals. Infectious diseases are a major challenge in livestock production because they can reduce productivity, increase treatment costs, affect animal welfare, and threaten the economic sustainability of farming systems. Traditional breeding has helped develop animals with improved resistance to many diseases, but progress can be slow when resistance is controlled by several genes or when reliable genetic information is limited. Genome editing provides an additional approach by allowing researchers to make targeted changes to specific DNA sequences that influence disease susceptibility or immune function. When carefully developed and responsibly applied, this technology could complement conventional breeding and genomic selection to support healthier and more resilient animal populations.
- Disease resistance is a complex biological characteristic. Some animals are naturally less susceptible to particular pathogens because of differences in their immune systems, cell receptors, or other biological processes. These differences may arise from naturally occurring genetic variation that has developed over many generations. Researchers can investigate such variation to identify genes and genetic pathways associated with resistance. Genome editing may then be used to study or reproduce selected genetic changes in laboratory models or, where scientifically justified and legally permitted, in livestock. The main objective is not simply to alter an animal’s DNA, but to understand how a specific genetic change affects the interaction between the host and a disease-causing organism.
- One important application of genome editing is the modification of genes that pathogens use to enter animal cells. Certain viruses and other pathogens depend on particular host-cell proteins to establish infection. If a genetic variant changes the structure or availability of one of these proteins without seriously affecting its normal function, it may reduce the pathogen’s ability to infect the animal. Researchers can investigate these mechanisms through targeted editing and controlled disease studies. However, changing a cell receptor can also interfere with essential biological processes, so the potential benefits must be evaluated alongside possible effects on growth, reproduction, metabolism, immunity, and general health.
- Porcine reproductive and respiratory syndrome (PRRS) is an important example of disease-resistance research in livestock. The disease affects pigs and can cause reproductive problems, respiratory illness, reduced growth, and substantial economic losses. The virus uses a host-cell protein called CD163 to enter susceptible cells. Research has demonstrated that targeted modification of CD163 can provide resistance to PRRS virus under studied conditions. This work illustrates how understanding the biological mechanisms of infection can help researchers identify specific genetic targets for disease-resistance strategies. Nevertheless, broader evaluation is necessary to assess performance across different production environments, pathogen variants, and animal populations.
- Genome editing is also being investigated as a potential tool against other important animal diseases. In cattle, researchers are exploring genetic changes that could improve resistance to infectious diseases and reduce susceptibility to particular pathogens. In poultry, genome-editing research may help identify host genes involved in viral infection and immune responses. Similar approaches are being investigated in other livestock species. The suitability of each application depends on the biology of the disease, the genetic mechanisms involved, the availability of reliable experimental evidence, and the feasibility of introducing a beneficial change without producing unwanted effects. Results obtained in one species or against one pathogen cannot automatically be applied to other animals or diseases.
- A major advantage of genome editing is its potential precision. Conventional breeding relies on inherited variation and recombination across the genome, whereas genome editing can be directed toward a selected DNA sequence. This may allow researchers to investigate a candidate gene more directly or introduce a particular genetic change without waiting for multiple generations of selection. However, the word precision should not be interpreted as a guarantee of perfect outcomes. Editing can produce unintended DNA changes, incomplete editing, or unexpected biological effects. The consequences of a genetic modification may also depend on the animal’s genetic background and its environment. Comprehensive molecular testing and long-term animal evaluation are therefore essential.
- Genome editing can complement genomic selection and conventional animal breeding. Genomic selection uses information from markers distributed across the genome to estimate the genetic merit of animals for traits such as disease resistance, growth, fertility, and feed efficiency. Genome editing, in contrast, makes a targeted change to DNA. These methods serve different purposes but may contribute to a coordinated breeding strategy. Genomic studies can help identify promising genetic targets, while genome editing can test whether changing a particular sequence produces the expected biological effect. If a beneficial edit is shown to be safe, effective, and legally acceptable, breeding programmes may still be needed to evaluate its inheritance, performance, and suitability within wider populations.
- An important consideration is whether disease resistance is controlled by a single gene or by many genes. Some resistance mechanisms depend strongly on a specific host factor, making them potential candidates for targeted modification. Other diseases are influenced by numerous genes, immune-system interactions, environmental conditions, nutrition, and management practices. For these complex traits, modifying one gene may produce only a limited improvement or may affect other important characteristics. A broader strategy that combines genetic selection, disease surveillance, vaccination where appropriate, biosecurity, nutrition, and good husbandry may therefore provide more reliable protection than relying on genome editing alone.
- Genetic diversity is another critical issue. A genetic change that protects animals against one disease could become widely distributed if animals carrying it are used extensively in breeding. Excessive reliance on a narrow set of genetic variants may reduce diversity or make a population more vulnerable to other diseases and environmental challenges. Breeding programmes should therefore monitor genetic variation, maintain effective population sizes, and consider the potential effects of selected edits on the wider genome. Disease resistance should be assessed alongside fertility, longevity, productivity, adaptability, and other traits important for long-term population health.
- Animal welfare must remain central to the development of genome-edited livestock. A successful intervention should reduce disease and suffering without introducing new health problems. Researchers need to examine animal development, behaviour, reproduction, immune function, and susceptibility to other conditions. They must also consider whether resistance to a particular pathogen could change disease transmission or create new management challenges. Independent scientific review, transparent reporting, and appropriate follow-up are important for identifying risks that may not be apparent during early experiments.
- The responsible use of genome editing also requires attention to ethical, regulatory, and economic questions. Regulatory frameworks differ between countries and may depend on the type of edit, the organism involved, and the intended use. Some jurisdictions regulate genome-edited animals under rules for genetically modified organisms, while others use approaches that distinguish certain edits from the introduction of foreign DNA. Developers must comply with applicable requirements for research, animal welfare, environmental assessment, food safety, traceability, and marketing. Public communication is equally important because consumers and producers may have questions about food products, animal welfare, environmental effects, and how genome-edited animals differ from conventionally bred animals.
- The economic value of disease-resistance editing depends on more than the technical success of changing a gene. Costs associated with research, testing, regulatory approval, breeding, and monitoring must be compared with the expected benefits, such as reduced disease losses, lower treatment expenses, improved survival, and more consistent production. Access to the technology is also important. If its use is limited to a small number of highly specialized breeding companies, benefits may not reach all livestock producers. Collaboration among researchers, veterinarians, breeding organizations, farmers, regulators, and public institutions can help ensure that potential advantages are evaluated fairly and responsibly.
- Genome editing does not eliminate the need for established disease-control measures. Vaccination, hygiene, biosecurity, veterinary care, appropriate stocking densities, good nutrition, and responsible animal movement remain essential components of disease prevention. Genetic resistance may reduce the likelihood or severity of infection, but it does not necessarily prevent every infection or stop all transmission. Pathogens can also evolve, and a genetic change that is effective against one strain may be less effective against another. Continued disease monitoring and flexible management strategies are therefore necessary to maintain long-term protection.
- Future progress in genome editing for disease resistance will depend on advances in genomics, immunology, pathogen biology, and animal breeding. Researchers are working to improve the identification of suitable targets, increase editing accuracy, detect unintended changes, and evaluate the effects of modifications across different genetic backgrounds. Combining these advances with genomic prediction and detailed health records may help breeding programmes make better-informed decisions. However, each proposed application requires evidence that the edit produces a meaningful benefit under realistic conditions and does not compromise other important traits.
- In conclusion, genome editing has significant potential to contribute to disease resistance in livestock by enabling researchers to investigate and modify specific genetic mechanisms involved in infection. Research involving PRRS resistance in pigs demonstrates how detailed knowledge of host-pathogen interactions can lead to promising targeted approaches. At the same time, technical precision alone is not sufficient to establish that a genetic modification is safe, effective, or appropriate for widespread use. Responsible development requires rigorous testing, long-term welfare assessment, protection of genetic diversity, transparent regulation, and integration with established disease-control practices. When these conditions are met, genome editing may become a valuable complement to conventional breeding and genomic selection, supporting healthier animals, more resilient livestock populations, and more sustainable animal production.
