InDel mutations within the bovine PER2 gene are significantly associated with reproductive traits

Functioning as a key regulator of circadian rhythms, the PER2 gene exerts a substantial impact on the reproductive traits of animals. However, the effect of the PER2 gene on ovarian development remains unclear. In order to examine the relationship between bovine reproductive trait and the PER2 gene, a total of 901 ovarian samples were collected, categorized into different oestrus cycles (proestrus, oestrus, post-oestrus, anoestrous), and subjected to analysis for two potential insertion/deletions (InDels) in the PER2 gene. Through agarose gel electrophoresis and DNA sequencing, two polymorphic deletion mutations (P2-D_5-bp, P3-D_13-bp) were identified. Furthermore, a significant association between mature follicle diameter and P2-D_5-bp was found (P < 0.05). Additionally, several significant correlations with ovarian length, width, height, and white body diameter were found for P3-D_13-bp (P < 0.05). These findings suggested that the bovine PER2 gene plays an important role in above-mentioned reproductive traits, offering new avenues for improving cow fertility through marker-assisted selection (MAS).