Goats’ Litter Size Concerning Bone Morphogenetic Protein 15 Gene Variations

Bone morphogenetic protein 15 (BMP15), a member of the transforming growth factor-β (TGF-β) superfamily, plays essential roles in follicular development and ovulation. Single nucleotide polymorphisms (SNPs) in the BMP15 gene have been associated with litter size in multiple livestock species, yet no comprehensive systematic review has synthesized findings across goat breeds. This systematic review aimed to evaluate the association between BMP15 genetic variations and litter size in goats. We conducted a systematic search of four databases (PubMed, Web of Science, ScienceDirect, and Google Scholar) following PRISMA guidelines. Ten studies met inclusion criteria, encompassing [X goats across Y breeds]. A total of 16 unique SNPs in the BMP15 gene were identified across multiple goat breeds. Nine SNPs (g.963G>A, g.1050G>C, g.735G>A, g.754G>T, g.781C>A, g.1083T>G, g.718C>T, g.6051G>A, g.6124C>G) demonstrated significant associations with increased litter size, suggesting their potential as genetic markers for selective breeding programs aimed at improving reproductive performance. Meta-analysis revealed [effect size] for the most frequently studied polymorphisms. Study quality assessment indicated [brief quality summary]. These findings support a significant association between specific BMP15 polymorphisms and litter size in goats. However, geographic and breed-specific variation, limited sample sizes in individual studies, and publication bias warrant cautious interpretation. Future research should prioritize large-scale, multi-breed validation studies and functional characterization of identified variants to facilitate marker-assisted selection for enhanced reproductive traits in goat breeding programs.