Assessment of nucleollus parameters depending on the genotype of sheep

In the course of the research, the morphometric and photometric parameters of the NOR of sheep were studied depending on their genotype. Differences in the number of nucleoli in the cells between the studied groups of animals were revealed. In purebred Romanov sheep (group I), the maximum number of NORs was observed in the amount of 11 pcs, the minimum - 1 pcs. While in group II these figures were 8 pcs and 1 pc, respectively. The coefficient of variation of the average value of the nucleolus area reached 52.8 %, the indicator of the average NOR area of sheep, regardless of the genotype, was 376.87 µm2. The difference in the average background density was statistically significant between the animals of groups I and II, and in Romanov sheep it was less by 5.3 % (P