Abstract
Background:
Japanese quails (Coturnix japonica) are a poultry species that is kept for meat and egg production. Genetic improvement in Japanese quails is important to increase quail farmers’ income. Molecular selection can be applied in Japanese quails to increase productivity traits.

Aim:
This study aimed to determine the effects of coturnine NR2E1 gene polymorphism on slaughter weight, carcass weight (CW), and carcass percentage (CP).

Methods:
Fifty female Japanese quails (Coturnix japonica) were used as experimental birds. The birds were maintained under an intensive management system. A method based on polymerase chain reaction (PCR) followed by restriction fragment length polymorphism analysis was used to detect a g.462C>G mutation site on the NR2E1/PstI gene.

Results:
The results showed that the genetic diversity in the mutation site under study was high, with a polymorphic informative content value of more than 0.30. In addition, three genotypes of CC, CG, and GG were observed in the birds under study, with allele frequencies of 0.42 (C) and 0.58 (G). According to the Chi-square (χ2) value, the genetic diversity in the studied birds was not under genetic equilibrium (χ2>5.99). Nonetheless, polymorphism in g.462C>G was not significantly associated with the economic traits of the studied birds. Nonetheless, the heterozygous birds had
higher CW and CP traits than other genotypes.

Conclusion:
The coturnine NR2E1/PstI gene was polymorphic with high genetic diversity. However, no significant association was found between the NR2E1/Pst1 gene polymorphism and economic traits for Japanese quails under study. In the future, in-depth research on the coturnine NR2E1 gene involving a large sample and different gene regions is important to accurately obtain the genetic marker for economic traits.

Key words: Economic traits; NR2E1 gene; PCR-RFLP; Polymorphism; Japanese quails.