Discovery of novel insertion SNPs in the ADRB2 gene associated with sheep growth performance

Abstract

The beta-adrenergic receptor-2 (ADRB2) is a crucial gene known to directly influence growth and metabolic traits; however, this association has not yet been investigated in sheep. The potential association between ADRB2 and growth traits in two commercially important sheep breeds with differing growth characteristics, the Iraqi Awassi and Iranian Karakul was investigated to evaluate the biomarker potential of ADRB2. A total of 172 lambs (88 Awassi and 84 Karakul) were included in the study. In both breeds, various growth traits were correlated with ADRB2 gene variations at three-month intervals from birth to one year of age. All samples were genotyped by amplifying up to 91 % of the coding regions within the ADRB2 gene, followed by Sanger sequencing. Out of twenty-seven SNPs identified in the ADRB2 gene, fourteen novel insertion SNPs were detected constituting 51.9 % of the total polymorphism. Whereas nine (33.3 %) silent SNPs and four (14.8 %) missense SNPs were respectively identified. Three of the identified insertions (105–106insT, 1024–1025insA, and 1065–1066insA) demonstrated various intensities of associations with the growth traits measured. While 105–106insT and 1024–1025insA showed consistent significant effects on most growth traits, the 1065–1066insA SNP’s influence was confined to a few key metrics. The linkage disequilibrium plot data showed little to no co-inheritance between these SNPs with their neighbors, as the three insertion SNPs demonstrated a relatively independent transmission tendency across generations. The variable levels of significant associations observed between the three SNPs and growth traits are primarily attributed to a translation frameshift, suggesting that these novel insertions could serve as valuable markers for evaluating growth traits in both breeds.