Formation of the genetic structure of cattle populations by single locus DNA fragments depending on their productivity direction and origin

Abstract

Aim. Our work was aimed at investigating the specificities in the formation of the genetic structure of populations depending on the productivity direction of cattle, bred in Ukraine, using single locus DNA fragments, and studying the impact of the parental form on genetic polymorphism of modern intensive specialized breeds as a factor. Methods. The following methods were used in the work: veterinary methods (peripheral blood sampling); molecular-genetic meth- ods (the isolation and genotyping of DNA samples of dairy (83 animals), meat (192 animals) and aboriginal (43 ani- mals) cattle, bred in Ukraine, were performed by 10 microsatellite loci from the list, recommended by the International Society for Animal Genetics (ISAG); the complex of statistics methods was used for mathematic-statistical analysis, using modern software. Results. The analysis by 10 microsatellite loci demonstrated the specificities of genetic dif- ferentiation and the similarities between the investigated cattle populations, bred in Ukraine. Our results provide new information about the impact of artificial selection factors on single locus DNA fragments under the specialization of cattle breeds. The impact of the factor of ancestral form on the genetic structure was determined and confirmed by the same polymorphism spectra of the investigated DNA fragments in the maternal and derivative breeds. Another con- firmation was found in the differences, observed in animals of different productivity directions, which are a probable result of the breed-forming process, demonstrated by the results of the mathematic calculations of the data obtained. It was shown that microsatellite DNA loci are highly informative markers of genetic processes, occurring in domestic cattle populations. Conclusions. The specificities in the formation of the genetic structure of populations depending on the productivity direction of animals were determined. The impact of the parental form on genetic polymorphism of modern intensive specialized breeds was noted. It was found that among 10 microsatellite loci, used by us, there were loci in each group of animals, regarding which the hypothesis about their neutrality was reliably rejected accord- ing to the results of Ewens-Watterson test: for dairy cattle (INRA023, ETH3, ETH225, BM1824, BM2113, ETH10 and SPS115), for meat cattle (TGLA122 and ETH225), and for aboriginal cattle (TGLA126, INRA023 and TGLA227). We determined a high level of genetic diversity, remarkable for each investigated cattle population, bred in Ukraine, and general tendencies of differentiation in the selected populations depending on the targeted breeding work, on the level of polymorphism of microsatellite DNA loci (Friedman’s test: P < 0.01), and a similar genetic picture for a number of loci of investigated DNA fragments, which may be related to the history of creating these breeds.