A meta-analysis study of the association between FecB polymorphism and litter size in sheep

In the current study, a meta-analysis was carried out by merging outcomes resulting from 26 published studies in various breeds of sheep to assess the influence of the FecB gene on litter size by applying the additive, recessive, dominant, and co-dominant genetic models. The model with random effects was used for data analysis according to the Cochran Q test and I2 quantity statistical measures. Standardized mean difference (SMD) was applied to measure the size effects of ' +' and B alleles of FecB on the litter size. The significant effect (P<0.01) of FecB genotypes on the litter size was identified under the additive (SMD = 0.511), dominant (SMD = 0.469) and recessive (SMD = 0.255) models. An increase in the litter size by approximately 0.47 lambs (Dominant model) was associated with the first copy of the FecB gene and 0.25 lambs (Recessive model) with the second copy of FecB. The findings of the current study supported the idea that BMPR1B would fundamentally influence the litter size in sheep. Subsequently, it may be utilized in marker-assisted selection programs to improve the genetic merit of litter size in the future. Introgression this gene through crossbreeding programs in low prolific breeds may improve reproductive performance.