In the dissertation work complex researches were carried out that included the task of studying the polymorphism of microsatellites and quantitative trait loci in the populations of local chicken breeds of Ukrainian selection, analysis of associations between detected polymorphic genes with chicken productive traits, optimization of DNA-typing methods of experimental chicken’s populations using SSR and Indel molecular markers. The genetic structure of the populations of chickens of White Plymouth Rock (G-2 line), Birkivska Barvista (line A), Poltava clay (line 14) and Rhode Island Red (line 38) for polymorphism of quantitative trait loci (PRL, PRLR, GH, GHR, IGF-I, PIT-1, TGF-β1, TGF-β2, TGF-β3, Mx) was studied. As the result of analysis of nucleotide sequences of the fourth intron of chicken growth hormone gene, a novel polymorphism in AluI restriction site (cytosine to thymine transition in Chr27:1788455 position) was detected. Primers flanking the fragment of the fourth intron of 460 bp in size, which contains polymorphic AluI restriction site, were developed. It was shown that growth hormone gene (in accordance with AluI polymorphism in 1788455 position) is polymorphic in all experimental chicken populations. C→T transition was present for the vast majority individuals and comprised 70–96%. According to results of the research of general indexes of heterozygosity for all polymorphic loci, the lowest values of observed and expected heterozygosity were characteristic for line 14 of Poltava clay breed (0,31 and 0,33), the highest – for line A of Birkivska Barvista breed (0,42 and 0,41). Chicken breed populations of White Plymouth Rock (line G-2) and Rhode Island Red (Line 38) occupied an intermediate position (0,36; 0,38 and 0,39; 0,39, respectively). By results of the research it is shown that the most genetically distant breeds were Birkivska Barvista and Rhode Island Red chicken breeds (24,9% of differences). At the same time, the differences of egg-laying chicken lines from breeds of egg-laying–meat productivity direction were maximally expressed (23–25% of differences in allelic variants of loci). The difference between meat–egg-laying and egg-laying–meat chicken breeds was not expressed enough. Maximum differences were noted between populations of Poltava clay and Plymouth Rock white (11,2%), minimum – between Rhode Island Red and White Plymouth Rock (4,2%). In turn, the value of the genetic distance between the two egg-laying–meat breeds was 7,1%. The association of different allelic variants of detected polymorphic loci with the manifestation of economically useful traits was established. For each experimental population, complexes of desirable genotypes corresponded by productivity directions were identified. The revealed genotypes for each of the loci were associated with the manifestation of elevated values of indexes of live weight, carcass weight, weight of thighs, shin, pectoral muscles and stomach.
