Identification of 24bp indel(s) Polymorphism in the Promoter Region of prolactin Gene and its Association with Broodiness in Tellicherry Native Chicken

Background: Broodiness is a sex linked behavioural trait observed in most of the domestic fowls and it’s also known as incubation behaviour. Prolactin (PRL) is the principal gene which plays a crucial role to the onset and maintenance of broodiness in birds. The present study was aimed at identification of 24bp (insertion-deletion) indel polymorphism at the promoter region of prolactin gene and its association with broodiness in Telllicherry native chicken population. Methods: A total number of 200 birds of Tellicherry native chicken were randomly selected from All India Co-ordinated Research Project (AICRP) on poultry improvement, Mannuthy, Thrissur, Kerala. Blood samples were collected from the wing vein under aseptic condition and isolation of Genomic DNA was done. Isolated DNA samples were subjected to polymerase chain reaction (PCR) using specific set of forward and reverse primer to detect a 24bp indel polymorphism in the prolactin gene. PCR amplicons were subjected to further molecular analysis. Result: According to the polymorphic patterns birds were categorized to three different genotypes viz., II (insertion-insertion), ID (insertion-deletion) and DD (deletion-deletion). The genotype and allele frequency was calculated and the frequency of I allele (0.6975) was found to be higher than D allele (0.3025). Results of this study suggest that the incubation behaviour could be eliminated in Tellicherry native chicken population by increasing the frequency of I allele upon selective breeding which may enhance the egg production. Therefore, this 24bp indel polymorphism could be used as a molecular marker in poultry breeding.