International Journal of Molecular Veterinary Research, 2024, Vol.14, No.5, 211-218 http://animalscipublisher.com/index.php/ijmvr 213 3 Genetic Mechanisms of Disease Resistance in Goats 3.1 Role of the immune system in disease resistance The immune system plays a crucial role in disease resistance in goats, as it is responsible for identifying and combating pathogens. Studies have shown that genetic variations can significantly influence the immune response in goats. For instance, the T cell receptor signaling pathway has been identified as a key differentiator between genotypes resistant and susceptible to gastrointestinal nematode (GIN) infections, with 78% of the genes involved in this pathway showing genomic variants (Aboshady et al., 2021). Additionally, the activation of immune responses, such as the Th1 and Th2 pathways, has been observed in resistant goats, indicating a robust immune response to infections like Haemonchus contortus (Aboshady et al., 2020). 3.2 Genetic basis of resistance and susceptibility The genetic basis of disease resistance and susceptibility in goats is complex and involves multiple genes and genetic variations. Single nucleotide polymorphisms (SNPs) have been identified in various genes associated with resistance or susceptibility to diseases such as pneumonia and GIN infections. For example, SNPs in genes like SLC11A1, CD-14, and TLRs have been linked to pneumonia resistance in Baladi goats (Ateya et al., 2023). Similarly, genetic variations, including SNPs, insertions, and deletions, have been found to distinguish resistant and susceptible genotypes in Creole goats (Aboshady et al., 2021). These genetic differences underline the importance of understanding the genetic architecture of disease resistance for effective breeding programs. 3.3 Genetic markers for disease resistance traits Genetic markers are essential tools for identifying and selecting disease-resistant traits in goats. The identification of specific SNPs and other genetic variations provides valuable markers for breeding programs. For instance, genome-wide association studies (GWAS) have identified candidate genes associated with GIN resistance in Creole goats, such as those related to immune response and inflammation processes (Silva et al., 2018). Additionally, the IL-33 gene has been highlighted for its role in enhancing immune resistance to nematode infections, serving as a potential genetic marker for breeding programs (Asif et al., 2017). These markers facilitate the selection of goats with enhanced disease resistance, contributing to more sustainable and profitable goat farming practices (Amayi et al., 2021). In summary, the genetic mechanisms of disease resistance in goats involve a complex interplay of immune system functions, genetic variations, and identifiable genetic markers. Understanding these mechanisms is crucial for developing effective breeding strategies to enhance disease resistance in goat populations (Zheng et al., 2020). 4 Advances in Genetic Selection Methods 4.1 Traditional breeding practices for disease resistance Traditional breeding practices have long been employed to enhance disease resistance in goats. These methods primarily rely on selecting individuals that exhibit desirable traits, such as resistance to specific diseases, and breeding them to propagate these traits in future generations. For instance, the genetic variability for resistance to diseases like caprine arthritis encephalitis (CAE) has been explored, indicating that direct genetic selection can effectively reduce disease prevalence in goat herds (Figure 2) (Schultz et al., 2020). Similarly, breeding programs targeting resistance to transmissible spongiform encephalopathies (TSE) have been proposed, focusing on alleles that confer resistance to classical scrapie8. These traditional methods, while effective, are often limited by the slow pace of genetic improvement and the complexity of accurately identifying resistant individuals. 4.2 Molecular tools in breeding: marker-assisted selection Marker-assisted selection (MAS) represents a significant advancement over traditional breeding by utilizing molecular markers linked to disease resistance traits. This approach allows for more precise selection of individuals carrying favorable genetic variants. For example, single nucleotide polymorphisms (SNPs) associated with resistance to pneumonia in Baladi goats have been identified, providing a basis for selecting animals with enhanced innate resistance (Ateya et al., 2023). Similarly, genomic variants linked to resistance against gastrointestinal nematode infections have been discovered, offering valuable resources for molecular breeding
RkJQdWJsaXNoZXIy MjQ4ODYzNA==