Study of Dopamine Receptor Gene Polymorphisms and Their Association with Growth and Egg Production Traits in West Azerbaijan Native Chicken

The objective of this study was to search for single nucleotide polymorphism (SNP)-type polymorphisms in the dopamine D1 receptor in West Azerbaijani native chicken and look for their association with egg production and body weight traits of chickens by polymerase chain reactionsingle strand conformation polymorphism (PCR-SSCP). For this purpose 180 blood samples were taken from native chickens in a poultry breeding station in West Azerbaijan, Iran. DNA was extracted from blood samples using the salting-out procedure. Specific primers were designed for PCR amplification of the 283 base segment of the dopamine D1 receptor gene. In order to demonstration of gene polymorphism, Singlestranded conformation polymorphism followed by sequencing was performed. Four samples from each banding pattern were sent for sequencing. The polymorphism was found in the D1 receptor gene (G123A). We detected three genotypes in DRD1 gene. The frequencies of three genotypes were 0.42 (AA), 0.49 (AG), and 0.09 (GG), respectively. The analysis of variance was performed using of SAS software. The Result shows that there was a significant relationship between genotypes of dopamine D1 receptor gene with egg production traits. This finding indicates that the dopamine D1 receptor gene was polymorphic and could be a candidate locus or linked to a major gene that influences reproductive traits in chickens.