Meta-analysis of association between c.963A>G single-nucleotide polymorphism on BMP15 gene and litter size in goats

Litter size is an important economic trait in the goat industry. Previous studies on the bone morphogenetic protein 15 (BMP15) gene detected some single-nucleotide polymorphisms (SNPs) such as c.963A [Formula: see text] G that were associated with an increase in ovulation rate and litter size. The aim of this study was to conduct a meta-analysis on the effect of this polymorphism on litter size. We gathered and pooled data from five eligible published studies. To investigate the effect of c.963A [Formula: see text] G on litter size, we utilized four different genetic models assuming dominant (GG [Formula: see text] GA vs. AA), recessive (GG vs. GA [Formula: see text] AA), additive (GG vs. AA) and co-dominant (GG [Formula: see text] AA vs. GA) model of inheritance. Data were analyzed under random-effects models based on the [Formula: see text] value. Furthermore, sensitivity analysis was carried out to validate the stability of results. The results showed that the c.963A [Formula: see text] G polymorphism is associated with litter size when applying a dominant model (standardized mean difference (SMD) is 0.815, 95 % CI [0.170, 1.461], [Formula: see text] value [Formula: see text] 0.013) and also with an additive model (SMD [Formula: see text] 0.755, 95 % CI [0.111, 1.400], [Formula: see text] value [Formula: see text] 0.022). However, the effect of c.963A [Formula: see text] G polymorphism was not significant under recessive (SMD [Formula: see text] 0.186, 95 % CI [ [Formula: see text] 0.195, 4.259], [Formula: see text] value [Formula: see text] 0.339) and co-dominant (SMD [Formula: see text] [Formula: see text] 0.119, 95 % CI [ [Formula: see text] 0.525, 0.288], [Formula: see text] value [Formula: see text] 0.568) models. Sensitivity analysis demonstrated that dropping studies with wide confidence intervals affects overall results under the assumption of an additive model. The meta-analysis results revealed that the AA genotype could be positively connected with litter size in goats.