Abstract
Background:
The cytochrome P450 family 26 subfamily B polypeptide 1 (CYP26B1) gene plays a crucial role in the regulation of retinoic acid (RA) metabolism, which is involved in various physiological processes in cattle, including reproduction and development. Therefore, studying genetic variation in the CYP26B1 gene can provide valuable baseline information for understanding its molecular diversity in cattle.

Aim:
This study aimed to identify single-nucleotide polymorphisms (SNPs) and assess the genetic diversity of CYP26B1 in Bali bulls.

Methods:
Blood samples were collected from 10 Bali cattle bulls at the Artificial Insemination Center in Singosari, Malang, East Java, Indonesia. The coding region of CYP26B1 was amplified and sequenced. SNP identification and sequence analyses were performed using the MEGA software version 12. Allele and genotype frequencies, observed and expected heterozygosity (Ho and He), and Hardy–Weinberg equilibrium were evaluated using the chi-square (χ²) test.

Results:
Six single nucleotide polymorphisms were identified within the 1.539-bp coding region of the CYP26B1 gene, namely c.528 C>T, c.624 G>A, c.948 G>A, c.1005 C>T, c.1098 G>T, and c.1125 G>A. Five SNPs showed an allele frequency of 0.95/0.05, while SNP c.1125 G>A showed an allele frequency of 0.40/0.60. All SNPs identified were synonymous and did not result in amino acid substitutions. None of the SNPs within this sample deviated from the Hardy–Weinberg equilibrium (χ² = 1.7–3.2; p > 0.05).

Conclusion:
The SNPs identified in Bali bulls indicate low to moderate genetic variation among the individuals sampled. These findings provide preliminary molecular information that may serve as a reference for future studies using larger sample sizes and functional approaches to clarify the potential relevance of CYP26B1 variation.

Key words: Bali cattle; CYP26B1 gene; Candidate gene; Genetic diversity; SNP.