G. A. Lihodeevskiy1, O. A. Minina1 , P. S. Bogatova1 , O. E. Lihodeevskaya1 , O. G. Loretts1 , O. S. Chechenikhina2
1 Ural State Agrarian University, Ekaterinburg, Russia
2 Ural State University of Economics, Ekaterinburg, Russia
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Volume 25 No. 12
Date of paper submission: 01.08.2025, date of review: 09.10.2025, date of acceptance: 29.10.2025.
Published: 12/31/2025
Abstract. The genetic structure of dairy cattle populations reflects both historical trends and the directed influence of contemporary breeding and selection practices. Over the last decade in the Sverdlovsk region, through intense expansion, there has been a transition from black-and-white Urals type cattle to the Holstein breed, which altered the gene pool structure of the herd. Linkage disequilibrium (LD) is a key population-genetic indicator reflecting nonrandom association of alleles at different loci and allowing identification of traces of artificial selection in populations of farm animals. Changes in breed composition of the population and intensive selection of dairy cattle for productivity traits lead to changes and formation of new specific patterns of LD that can significantly differ between generations. The purpose of the study is to determine variable regions in the genomes of past and present-day dairy cattle in the Sverdlovsk region. Methods include genotyping two generational groups – black pied Urals-type cattle and modern Holstein cattle – using medium-density DNA microarrays followed by assessment of differences in LD. Scientific novelty lies in the fact that no previous studies have been conducted in the Sverdlovsk region aimed at identifying specific regions affected by selection or genetic drift. Results show an increase in the average R2 by 40% in younger compared to older individuals. Twenty-four genomic regions with increased variability of LD were identified, containing 75 protein-coding genes grouped into five functional clusters associated with lipid metabolism, immune response, inflammatory processes, and energy exchange. Special attention is drawn to the region BTA9:74.04–78.69 Mb, where the most significant differences between populations are observed, and which contains genes related to immune response and metabolism.
Keywords: population genetics, genetic variability, breed substitution, genomic selection, DNA microarray, holsteinization, dairy farming, black pied cattle, linkage disequilibrium, loci
Acknowledgements. The study was carried out within the framework of the Russian Ministry of Agriculture’s state assignment (registration number 124061300024-1).
For citation: Lihodeevskiy G. A., Minina O. A., Bogatova P. S., Lihodeevskaya O. E., Loretts O. G., Chechenikhina O. S. Comparative characterization of linkage disequilibrium in generations of dairy cattle in the Sverdlovsk region against the background of breed substitution. Agrarian Bulletin of the Urals. 2025; 25 (12): 2144‒2157. https://doi.org/10.32417/1997-4868-2025-25-12-2144-2157 (In Russ.)
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