Patterns of homozygosity (ROH) as markers of genetic structure of Duroc and Large White pig populations

T. S. Romanets¹, S. Yu. Bakoev² , E. A. Romanets¹ , E. N. Gnedko¹ , A. A. Alekseev¹

¹ Don State Agrarian University, Persianovskiy settlement, Rostov region, Russia

² All-Russian Research Institute of Breeding, Lesnye Polyany, Moscow region, Russia

E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Volume 26 No. 6

Date of paper submission: 26.02.2026, date of review: 04.05.2026, date of acceptance: 12.05.2026 

Published: 06/30/2026

Abstract. Intensive artificial selection, inbreeding, and population bottlenecks in pig production have led to the accumulation of homozygosity (ROH), reducing genetic diversity. ROH analysis allows for the accurate assessment of recent inbreeding and the identification of selection loci. The purpose of this study was to conduct a comparative genomic analysis of homozygosity patterns (Runs of Homozygosity, ROH) in Large White and Duroc pig breeds, as well as to quantitatively assess inbreeding and identify specific characteristics of the chromosomal distribution of homozygous segments. Methods of the study included genotype analysis of 900 Large White and 1075 Duroc pigs, followed by ROH identification and calculation of the inbreeding coefficient (F_ROH). Genetic differentiation was assessed using Multidimensional Scaling (MDS). ROH were characterized by analysis of their length (L_ROH) and chromosomal localization. Results demonstrated clear genetic discreteness of the breeds. The Duroc breed exhibits a significantly higher level of inbreeding (F_ROH = 0.2334) and a greater total ROH length (L_ROH 146 Mb) compared to the Large White breed (F_ROH = 0.1447; L_ROH 94 Mb). Furthermore, a breed-specific ROH distribution was established: in Durocs, localization in the central regions of chromosomes is dominant, whereas in Large Whites, ROH are more often found in telomeric regions. The scientific novelty of this study lies in the comprehensive genomic comparison of two key pig breeds – Large White and Duroc – through the analysis of ROH patterns. This study contributes to the understanding of chromosome-specific homozygosity distribution, which allows for a better understanding of the influence of various selection pressures on the gene pool of these breeds.

Keywords: homozygosity patterns, ROH, inbreeding, pigs, Large White breed, Duroc

Acknowledgements. The study was supported by grant No. 23-76-10009 from the Russian Science Foundation, https://rscf.ru/project/23-76-10009/

For citation: Romanets T. S., Bakoev S. Yu., Romanets E. A., Gnedko E. N., Alekseev A. A. Patterns of homozygosity (ROH) as markers of the genetic structure of Duroc and Large White pig populations. Agrarian Bulletin of the Urals. 2026; 26 (06): 1087‒1095. https://doi.org/10.32417/1997-4868-2026-26-06-1087-1095. (In Russ.) 

 

Download the full text of the article