Allele Distribution and Genetic Variation of the Leptin Gene in Laying Hens and its Relationship to Egg Production

Abstract

ABSTRACT. Egg production is a quantitative trait influenced by the interplay of multiple closely related genetic and physiological factors. Genes contribute to the regulation of hormonal functions and metabolism, playing a pivotal role in controlling egg production rates, continuity, and quality. This study aimed to determine the allelic distribution and genetic diversity of the leptin gene (LEPR) and to investigate its relationship to certain egg production traits in local laying hens. Fifty blood samples were collected from local hens, and DNA was extracted. Tetra-ARMS-PCR was used to determine genotypes and allele distribution. The results of molecular analysis showed the presence of three genotypes: AA, AC, and CC, with frequencies of 58%, 22%, and 20%, respectively. The frequency of the A allele was approximately 69%, compared to 31% for the C allele, indicating the dominance of the A allele in the experimental samples. A significant correlation was observed between genetic variation in the leptin gene, with the AC genotype resulting in the highest percentage of egg production (%HDP), while the AA genotype showed superiority in some traits related to egg weight and internal composition. No significant differences were recorded in most of the studied traits, except for some related to egg weight and shape index. The leptin gene plays a crucial role in regulating the productive performance of laying hens by influencing energy balance and physiological processes associated with reproductive activity. This highlights the potential use of the polymorphism of this gene as an assistive genetic marker in selection and genetic improvement programs, aiming to enhance egg production efficiency and improve the economic performance of local chicken flocks.