Genotypic Diversity Of Dopamine D1 Receptor Gene (DRD1) In Indigenous Chickens Of Marandi And Mazandarani Breeds

Prolactin gene plays a key role in the initiation and continuation of broodiness in chickens. Dopamine in the pituitary gland reduces the effect of prolactin. This research was conducted to investigate the allelic polymorphism of dopamine D1 receptor gene (DRD1) using PCR-RFLP method in Marandi and Mazandarani indigenous chickens. In this study, blood samples were collected randomly from 200 chickens and genomic DNA was extracted using salting out method. Amplification of the desired locus with 283 bp was performed using specific primers and the CfrI enzyme was used to identify the mutation in the desired locus. After digestion, for DRD1 marker site, three genotypes AA, AG and GG, and two alleles of A (with on band of 283 bp) and G (with two bands of 183 and 100 bp) were identified. Indigenous chicken masses were in the Hardy-Weinberg equilibrium. For Marandi and Mazandarani indigenous chicken masses, the Shannon information index in DRD1 marker site was 0.59 and 0.67, respectively, the fixation index was -0.09 and -0.19, respectively and the observed heterozygosity index was 0.44 and 0.58, respectively. Regarding the presence of polymorphism and mutation in the studied locus and by studying the traits of related to the observed genotypes, it is suggested that this locus can be used as an appropriate marker for breeding programs.