SEL’SKOKHOZYAISTVENNAYA BIOLOGIYA [AGRICULTURAL BIOLOGY], 2015, V. 50, ¹ 2, pp. 198-207 ISSN 2313-4836 (Online) Genetic structure of populations doi: 10.15389/agrobiology.2015.2.198rus doi: 10.15389/agrobiology.2015.2.198eng POLYMORPHISM OF GROWTH HORMONE, GROWTH HORMONE RECEPTOR, PROLACTIN AND PROLACTIN RECEPTOR GENES IN CONNECTION WITH EGG PRODUCTION IN POLTAVA CLAY CHICKEN R.A. KULIBABA National Academy of Agrarian Sciences of Ukraine, Borky, Zmiiv Region, Kharkiv Province, 63421 Ukraine, A b str a c t The molecular assisted selection in animals is based on polymorphism study of desired gene alleles related to economic important traits, particularly productivity parameters. <...> Allelic variants can be a result of different modification of DNA nucleotide composition, i.e. spot mutations leading to a single nucleotide polymorphism (SNP), insertions and deletions (indel), etc. <...> So far as the physiological effect of any hormone is known to be directly related to its receptor, it is advisable to study gene polymorphism of both hormones and their receptors. <...> In the Ukraine the relationship between polymorphism of the genes mentioned hereinabove and hen performance was not still studied. <...> The genetic structure of Poltava Clay chicken egg-and-meat breed (line 14, = 98, laboratory population of State Poultry Research Station of the National Academy of Agrarian Sciences of Ukraine) was studied on growth hormone ( receptor genes ( ), growth hormone receptor ( ), prolactin ( and ( -AluI), respectively, in ) and prolactin ). <...> Gene polymorphism was determined by PCR-RFLP analysis and by comparative analysis of amplified fragment length when studying insertion in the prolactin locus. <...> The prolactin gene (24 indel) and prolactin receptor gene were monomorphic. <...> The relationship of different genotypes of prolactin, growth hormone, and growth hormone receptor genes with egg productivity was studied. <...> All studied polymorphic loci were in Hardy-Weinberg equilibrium in population of Poltava clay chicken breed. <...> It is shown the significant differences in the productivity of individuals of different genotypes for the loci of prolactin ( the individuals with genotype -AluI) and growth hormone ( - - The egg weight at 30th week of exceeded that in the individuals with genotype reached 201.50±8.43, and in - against 50.95±0.54 g in the individuals with heterozygous individuals with genotype life was 54.80±1.44 g in the individuals <...>