PSX-25 The distribution of runs of homozygosity in nine native Russian sheep breeds

Abstract

Abstract Native coarse wool fat-tailed sheep breeds are the main producers of mutton in mountainous, steppe and semi-desert regions of Southern Russia. An assessment of homozygosity is required to prevent loss of genetic diversity and inbreeding depression onset. The aim of our work is estimation of genomic inbreeding and distribution of the runs of homozygosity (ROH) segments in Russian sheep breeds. Sample collection included Andean (n = 20), Buryat (n = 18), Buubei (n = 11), Edilbai (n = 20), Karachaev (n = 20), Kalmyk (n = 22), Karakul (n = 20), and Lezgin (n = 15) breeds. All sheep were genotyped using Ovine Infinium® HD SNP BeadChip (Illumina, USA). Quality control and raw data processing were performed in PLINK 1.9. A consecutive runs method implemented in the R package “detectRUNS” was used for estimation of ROH segments. We detected the ROH in all breeds with mean length ranging from 0.35 in Lezgin to 11.18 Mb in Karachaev. Andean had the greatest number of the ROH segments (total of 8496), while 3094 ROH segments were found in Buubei. Short ROH segments (< 2 Mb) were predominant in all breeds and varied from 96.83% in Andean to 99.87% in Buubei. The frequencies of the ROH segments of 8–16 Mb ranged from 0.03% in Karakul to 0.18% in Andean. ROH segments of 8–16 Mb did not occur in the Buubei and Lezgin breeds. The ROH segments were found on all autosomes. The largest genome coverage in the ROH was identified on OAR1, OAR 12 and OAR 20 and the lowest was accounted for OAR 17, OAR 18 and OAR 19. The values FROH ranged from 0.042 in Buubei to 0.084 in Andean. Except of Andean, no traces of long-term inbreeding were detected in local breeds. The obtained data are relevant for future sustainable management of native fat-tailed sheep breeds in Russia. The study was funded by RSF No. 19-16-00070.