Polymorphisms of ADIPOQ gene and their association with growth and carcass traits in sheep

Abstract

Objective: In this study, polymorphisms and linkage relationship of ovine ADIPOQ (adiponectin) gene were investigated and their effects on some growth and carcass traits were estimated, so as to enrich the molecular genetic data for sheep. Method: Mutations in Exon-1 and Exon-2 of ADIPOQ gene were detected by PCR-SSCP in 8 commodity sheep populations, and the relationship between mutations in growth and carcass traits in New Zealand (NZ) Romney lambs was investigated using General Linear Models (GLMs). Result: In total, thirteen SNPs were detected in Exon-1 and Exon-2 regions of ovine ADIPOQ gene, and the nucleotide substitution c.46T/C in Exon-2 resulted in amino acid change (p.Tyr16His). Allele A₁ and B₁ were the dominant allele in Exon-1, Allele A₂ and D₂ were the dominant allele in Exon-2, and there were difference of allele frequencies between these two regions. The majority population was moderately polymorphic in all regions (PIC＜0.5), except Texel, Perendale and Dorset Down was low polymorphic in Exon-2 region (PIC＜0.25), and there was a high linkage relationship of these mutation and tend to shared genetic linkages (D'=0.952, r²=0.365). The association analysis showed that the mutations in Exon-1 region of ovine ADIPOQ gene had different effects on growth traits of male and female lambs. In male lambs, individuals with possessing allele A₁ had lower tailing weight, weaning weight and pre-weaning growth rate than those no-possessing (P＜0.05), but no associations were detected in female lambs (P＞0.05). In female lambs, individuals with possessing allele B₁ had higher tailing weight than those no-possessing (P ＜0.05), however, no associations were detected in male lambs (P＞0.05). And individuals with possessing B₁B₁ had higher tailing weight and weaning weight in male lambs. The carcass traits association analysis results showed that individuals with possessing allele A₁ had lower hot-carcass weight, loin yield, leg yield and total yield than those no-possessing (P＜0.05), and individuals with possessing allele B₁ had higher leg yield, proportion of led yield and lower proportion shoulder yield than those no-possessing (P＜0.05), individuals with possessing B₁B₁ had higher hot carcass weight, loin yield, leg yield and total yield (P＜0.05). Conclusion: Exon-1 and Exon-2 of ovine ADIPOQ gene had abundant polymorphisms, and SNP c.46T/C was non-synonymous. The mutations of Exon-1 of ovine ADIPOQ gene might affect some growth traits and carcass traits, and selecting sheep with allele B₁ and genotype B₁B₁, or eliminating ones with allele A₁ and A₁A₁ could improve some growth traits and carcass traits of Romney sheep.