Fertility-Associated Polymorphism within Bovine ITGβ5 and Its Significant Correlations with Ovarian and Luteal Traits

There is an urgent need to improve bovine fertility, and molecular marker-assisted selection (MAS) can accelerate this process. Genome-wide association studies suggest that Integrin β5 (ITGβ5) might affect fertility in bovines. As a member of the integrins family, ITGβ5 can bind to the extracellular matrix and mediate various cellular processes. In our study, primers spanning six potential insertion/deletion (indel) polymorphisms within the ITGβ5 gene were designed and 696 ovary samples from different individuals, the vast majority not in oestrum were collected for genetic variation detection. A deletion locus, rs522759246, namely P1-D_13-bp, was found to be polymorphic. The allele D frequency was 0.152 and the polymorphism information content (PIC) value was 0.224, indicating a low-degree PIC. This locus did not follow the Hardy-Weinberg equilibrium (p = 1.200E-23). Importantly, associations between P1-D_13-bp and ovarian morphological traits were established. Polymorphisms of this locus had significant correlations with ovarian width (p = 0.015). The corpus luteum is also linked to fertility and P1-D_13-bp was significantly correlated with corpus luteum diameter (p = 0.005). In conclusion, an indel mutation within the bovine ITGβ5 gene was identified, which was significantly associated with several ovarian and luteal traits.