Assessment of association between variants and haplotypes of the IGF2 gene in beef cattle

Insulin-like growth factor 2 (IGF2) is a fetal growth and differentiation factor that plays an important role in muscle growth and in myoblast proliferation and differentiation. The aim of this study was to examine the association of the IGF2 polymorphism with growth traits in beef cattle breed. Four single nucleotide polymorphisms (SNPs: 1-4) were identified in the bovine IGF2 by sequencing pooled DNA samples (Pool-Seq) and forced polymerase chain reaction-restriction fragment length polymorphism (Forced PCR-RFLP) methods. The result of haplotype analysis of four SNPs showed that eight haplotypes and eighteen combined genotypes were revealed, and the linkage disequilibrium and evolutionary relationship were assessed in 1522 individuals representing four purebred cattle breeds from China. The statistical analyses indicated that the 4 SNPs and 18 combined genotypes or haplotypes are associated with the body weight at 18 and 24 months in Jiaxian cattle population (P<0.05 or P<0.01). Our results provide evidence that polymorphisms in the IGF2 gene are associated with growth traits, and may be used for marker-assisted selection in beef cattle breeding program.