Insertion/deletion variants within the IGF2BP2 gene identified in reported genome-wide selective sweep analysis reveal a correlation with goat litter size

Insulin-like growth factor 2 m RNA-binding protein 2(IGF2 BP2,also called IMP2)plays an essential role in the development and maturation of germ cells and embryos and is a candidate gene for goat litter size,based on a previous genomewide selective sweep analysis.In this study,the m RNA expression level of IGF2 BP2 was found to be significantly higher in a single-lamb group than in a multi-lamb group.Insertions/deletions(indels)within the goat IGF2 BP2 gene,including P4-Ins-13 bp and P5-Del-12 bp,were verified in 918 Shaanbei White Cashmere(SBWC)female goats.The minor allelic frequencies(MAFs)of P4-Ins-13 bp and P5-Del-12 bp loci were 0.349 and 0.295,respectively.Analysis using the Chi-square(χ^(2))test showed that the genotype(χ^(2)=14.479,P=0.006)distribution of P4-Ins-13 bp was significantly different between the single-lamb and multi-lamb groups.Correlation analysis demonstrated that P4-Ins-13 bp was significantly associated with goat litter size(P=0.022),and individual goats with the homozygous deletion/deletion(DD)genotype produced more litters than other goats.Therefore,considered as a potential molecular marker significantly related to lambing traits,the P4-Ins-13 bp mutation of the goat IGF2 BP2 gene can be used in goat breeding with practical molecular marker-assisted selection(MAS)to optimize female reproduction and improve economic efficiency in the goat industry.