A novel association between hemoglobin subunit beta gene and reproductive performance in Awassi ewes

Abstract

Abstract This study was performed to assess the polymorphism in the HBB gene and its association with reproductive traits in Awassi ewes. Genomic DNA extracted from 124 and 100 Awassi ewes, respectively, produced single and twins. We amplified three exons in the HBB gene (exon 1, exon 2, and exon 3) to obtain the band (204 bp, 251 bp, and 222 bp) by PCR. Two genotypes were determined in 251 bp amplicon, AA and AG genotypes. Sequencing reactions detected a novel mutation in AG genotype, c.51983514 A > G, with a missense effect of p.K65R. A highly significant (P ≤ 0.01) association of p.K65R SNP with reproductive traits (especially composite reproductive traits, twinning rate, prolificacy and litter size) was reported, in which sheep having p.K65R SNP had a lower composite reproductive traits, twining rate, prolificacy and litter size than those without this SNP. This negative influence of p.K65R SNP was also confirmed by cumulative predictions performed by several in silico tools, which indicated a strongly deleterious impact of p.K65R SNP on hemoglobin. In conclusion, the interesting negative effect of p.K65R SNP has a considerable effect on reproductive performance (especially composite reproductive traits, twinning rate and prolificacy as well as litter size) in Awassi sheep. This manuscript strongly suggests the need to exclude ewes having p.K65R SNP when high values from higher reproductive performance are required.