The presented thesis reveals results of a comprehensive analysis of the polymorphism of DNA markers of artificial paddlefish population, reared under the conditions of three fish farms of Ukraine, including the «Dnieper sturgeon fish hatchery named after acad. S.T. Artyushhyk» (n=32, Сherson region), «Chernigivrybhosp» (n = 35, Chernihiv region), LTD «Fish farm «Mercury» (n = 38, Vinnytsya region).
Based on GenBank genetic database and FAO recommendations there were done the generalization and selection of the most polymorphic STR-loci specific for paddlefish. The following four DNA markers were identified as the most polymorphic and informative: Psp12, Psp21, Psp26, Psp28.
With the usage of an optimized multiplex PCR method there were evaluated, characterized and scientifically substantiated the features of the genetic structure of domestic paddlefish populations.
The specifics of the distribution of alleles and their frequencies for the Ukrainian paddlefish populations were established. In general, there was established mean number of allele for three populations at 22,7 alleles. The Kherson population was determined as the most polymorphous, for which 25 allelic variants were identified, while the Vinnytsia and Chernihiv populations were less polymorphic, for which 22 and 21 allelic variants were identified respectively.
There was scientifically confirmed the polymorphism of the studied microsatellite DNA loci of paddlefish according to the polymorphism information content (PIC = 0,569).
There was conducted a complex comparative study of the populations of this species from Ukraine, Poland and from the natural reservoirs of the USA using polymorphic microsatellite DNA markers. In this study there have been determined that average number of alleles per locus for hatchery reared Ukrainian (Na = 6,1) and Polish stocks (Na = 5,5) was lower, compared to populations from natural reservoirs (Na = 11,1).
The main features of the genetic polymorphism were analyzed. There was found that the observed heterozygosity calculated from gene frequencies in paddlefish groups from Ukrainian fish farms was higher than the expected value (Ho = 0,702; He = 0,619) as well as in compared Polish paddlefish stocks (Ho = 0,809, He = 0,699). Whereas, in wild stocks the observed heterozygosity was close to expected according to Hardy-Weinberg Equilibrium (HWE) (Ho = 0,813; He = 0,817). The mean fixation index (Fis) for Ukrainian paddlefish stocks averaged for three stocks at Fis = –0,124, while for Polish stocks an average value was Fis = –0,108, indicating the predominance of heterozygous genotypes in domesticated paddlefish stocks. However, for wild populations the calculated average Fis value was Fis = –0,002, indicating that the genotype frequencies in wild stocks were close to Hardy-Weinberg expectations. The established data showed that at this stage of paddlefish reproduction under aquaculture conditions there are a sufficient number of spawning individuals with heterozygous genotypes.
It was established the phylogenetic relationships between paddlefish populations. The indices of genetic distances and genetic identity between Ukrainian populations showed the high genetic relatedness for each of the three populations and confirmed the common origin of the studied fish groups. The genetic distinctions were observed between artificial and natural stocks, as well as between Ukrainian and Polish stocks, which allows considering the investigated fish groups as a potential source for the exchange and enrichment of paddlefish genetic resources.
