Polymorphisms of prolactin gene in a native chicken population and its association with egg production

The induction and regulation of broodiness is of the most important role of prolactin in avian species. The promoter region of the prolactin gene is an appropriate model for studying tissue-specific and hormonally-regulated activation of gene transcription. In this study, the association between prolactin promoter region alleles and egg production in Fars native chickens was investigated. In total, 100 laying hens, randomly selected from the flock of the Breeding Center for Fars Native Chicken, were genotyped for two single nucleotide polymorphisms (C-2161G and C-2402T), one 24-bp insertion-deletion at the site -358. The observed genotypic frequencies in the C-2161G site were CC (0.437), CG (0.435) and GG (0.101). Two alleles were found for the SNP of C-2402T with frequency of 0.34 for T and 0.66 for C. The 24-bp insertion-deletion at the site -358 was shown to be polymorph in the studied sample, with the observed genotyping frequency of 0.417 in II, 0.457 in ID and 0.126 in DD. Significant relationship was found between the SNPs and insertion-deletion genotypes with egg production (P<0.01).