Polymorphism of GTF2A1 gene is associated with litter size in sheep.

General transcription factor IIA subunit 1 (GTF2A1) is required for transcriptional activation from most promoters in eukaryotic transcription. Previous whole-genome association analyses articles have predicted the effect of this gene on lambing in sheep. In the study, a total of nine insertion/deletion (indel) variants named L1 to L9 in the gene were selected to detect in 550 Australian White sheep (AuW) adult ewes. The polymorphisms were detected in four loci (L1, L2, L3 and L8locus) and the polymorphism information content (PIC) values were 0.270, 0.375, 0.372 and 0.314. Further, our study revealed that L1, L2 and L3 loci of GTF2A1 gene were significantly related to the first parity litter size and the polymorphism of L8 was significantly correlated with litter size in the second parity. In details, for the first parity, individuals with the II genotype of the L1 locus had higher little size than that with the ID genotype, individuals with the ID and DD genotype of the L2 locus had higher little size than that with the II genotype, and individuals with the DD genotype of the L3 locus had higher little size than that with the II genotype. All four loci do not follow to Hardy-Weinberg equilibrium, and have no linkage between them. In conclusion, the polymorphisms of GTF2A1 were confirmed and analysis results demonstrated that there are some relevance between difference genotypes and litter size, and these findings may provide new insights for accelerating sheep molecular breeding through molecular marker-assisted selection (MAS).