author(s)
Chethan Raj R, Kanaka KK, Jeevan C, AR Sahu, Balraj S, Dhanpal and Mitek Tarang

abstract
Molecular markers already provide new opportunities to speed up selection of routinely measured traits or to select for new traits that are costly and/or difficult to record in farm animals and to improve animal production. A number of literature reports suggested that the SacI locus in intron 4 of cGH gene associated with egg number and laying rate. Melatonin regulates various biological functions through three different receptor subtypes – MTNR1A, MTNR1B, and MTNR1CMTNR1C (Mel1C), has been identified in amphibians and birds but not in mammals. MTNR1C SNPs were statistically significantly associated with AFE and egg number at 300 days. Vasoactive intestinal peptide (VIP) gene regulates prolactin secretion in poultry, where effects of VIP on the body depend upon vasoactive intestinal peptide receptors (VIPR-1 and VIPR-2). VIPR-1 gene is considered as an indicator to reduce hatchability and improve egg quality, and have association with lower age at first egg (AFE) and higher egg production at 300 days of age. So, main objective of this review is to provide ample information related to polymorphism in egg production linked genes and their association with economic traits in chicken.