# A Functional 67-bp Duplication Locating at the Core Promoter Region within the Bovine ADIPOQ Gene Is Associated with Ovarian Traits and mRNA Expression

## TL;DR

A 67-bp duplication in the ADIPOQ gene promoter is linked to ovarian traits and gene expression in Chinese Holstein cows, offering a potential genetic marker for improving reproductive efficiency.

## Contribution

The study identifies a novel functional duplication in the bovine ADIPOQ promoter associated with ovarian traits and gene expression.

## Key findings

- Three ADIPOQ genotypes (DD, ID, II) were identified in 2219 Chinese Holstein cows.
- The mutation is strongly correlated with ovarian traits like ovary weight and width.
- The ID genotype reduces ADIPOQ mRNA expression in ovarian tissue.

## Abstract

Our previous investigation identified a 67-bp variable duplication in the ADIPOQ promoter region, which may impact cow ovarian development. Our researchers looked into the relationship between ADIPOQ promoter variants and ovarian traits and mRNA expression in Chinese Holstein cows in order to gain a better understanding of how to maximize the milk production of these cows while preserving their reproductive efficiency. Three genotypes were found in 2219 samples, and there was a strong correlation between this mutation and ovarian traits. Moreover, the mutant phenotype dramatically decreased the expression of the ADIPOQ gene mRNA in ovarian tissue. To increase dairy cow fertility, it is crucial to identify the genes that govern ovarian features, given the significance of the ovarian in the female reproductive system. In order to enhance the reproductive quality of Chinese Holstein dairy cows, this study offers a theoretical framework and molecular breeding signals.

ADIPOQ plays a crucial role in regulating the reproductive system, but there are few reports on the effects of ADIPOQ on ovarian in dairy cows. Previous studies have verified the presence of a 67-bp mutation in the promoter region of the ADIPOQ gene. Hence, we employed ovarian tissues (n = 2111) and blood samples (n = 108) from Chinese Holstein cows as experimental samples to examine the association between ADIPOQ promoter variants and ovarian traits. We extracted DNA from these samples and conducted genetic typing identification on each sample using advanced techniques like PCR and agarose gel electrophoresis. Consequently, the DD, ID, and II genotypes were discovered. and it has been observed that the mutation frequency of this locus is low in the Chinese Holstein cow. Importantly, the correlational analysis unveiled a significant relationship (p < 0.05) between the weight of ovaries in late estrus and the width of ovaries during the estrus interval with the mutation. Result of the RT-PCR revealed that the ID genotype partially diminished the expression of the ADIPOQ gene. The results of this study suggest that the identified variable duplication could serve as a potential genetic marker for enhancing the ovarian traits of Chinese Holstein cows.