*2.4. Runs of Homozygosity Estimation*

For ROH calculation, we used a window-free method for consecutive SNP-based detection [29] implemented in the R package "detectRUNS" [30]. One SNP with a missing genotype and up to one possible heterozygous genotype was allowed in the run. The minimum ROH length was 1000 kb.

ROH were estimated for each animal and then categorized in the corresponding ROH length classes: (1–2 Mb, 2–4 Mb, 4–8 Mb, 8–16 Mb, >16 Mb). The total number of identified ROH was calculated for each length category in each of the individuals of each breed. The mean sum of ROH was computed by adding up the length of all ROH for each individual in the sheep populations and then the results were averaged per breed population.


**Table 2.** Mean ROH length and mean ROH number in Russian sheep populations.

<sup>1</sup> *n*—number of individuals; <sup>2</sup> Min—minimum values of estimations observed in individual animals within breeds; <sup>3</sup> Max—maximum values of estimations observed in individual animals within breeds.
