Exploration of the association between SMAD5 gene polymorphisms and litter size and growth traits in sheep (Ovis aries)

Abstract Background SMAD Family Member 5 (SMAD5) is a downstream mediator of BMP signaling and plays a biological role in cell proliferation, differentiation, development, and reproduction. This study aimed to evaluate the effect of mutations in the SMAD5 gene on litter size and growth traits in Garut sheep. Methods and Results A single nucleotide polymorphism (SNP) in the SMAD5 gene of Garut sheep was detected using DNA pool sequencing and forced sequencing methods. Three genotypes AA, AG, and GG were identified, with AG being the most prevalent. The detected locus exhibited a moderate level of genetic diversity (PIC = 0.36). Statistical analysis revealed that the SNP and its genotypes were associated with body weight, hip width, and wither height, with the GG genotype displaying higher values than the other genotypes. We also observed an association between genotypes and litter size at first parity, where the AG genotype showed higher results compared to the others. Conclusion These findings provide evidence that polymorphism in the SMAD5 gene was associated to growth traits and litter size at first parity, suggesting its potential utility for marker-assisted selection in Garut sheep breeding programs.