Cytogenetic Variability of the Hutsul Breed of Horses

Abstract

Goal. Study of features of karyotypic variability of Hutsul horses. Methods. Cytogenetic analysis, micronucleus test. Results. The average rate of genomic disorders (aneuploidy) was 10.8%, with a range of values of this variability of 8.8%–11.1% in animals of the LLC "Krai Neba" and the National Nature Park "Hutsulshchyna" with a statistically insignificant difference between the mean values. The multiple increase in the number of chromosomes, polyploidy, was in the range of 1.1%–2.0%, which does not exceed the species of this variability. The magnitude of the asynchronous divergence of the centromeric regions of the chromosomes was 2.0%–6.0%, which corresponds to the spontaneous level for horses as a whole (2.2%–9.1%). Structural chromosome abnormalities (chromosomal breaks) in the horses of the Krai Neba LLC farm were not detected, and in the animals of the Hutsulshchyna National Nature Park they were 1.1%. The range of variability of lymphocytes with a micronucleus for animals of two farms was 4.0–4.2‰. The number of dinuclear lymphocytes (6.2‰) exceeded the mitotic index (4.3‰) with an insignificant difference in the average values, which indicates the absence of radionuclide contamination of the territory. Conclusions. The average number of aneuploid cells – 10.8%, polyploid – 1.4%, asynchronous divergence of the centromeric regions of chromosomes – 3.9% and the proportion of chromosomal breaks – 1.1%. The proportion of lymphocytes with a micronucleus – 4.0–4.2–4, dinuclear lymphocytes – 6.2‰ and the mitotic index – 4.3‰, which indicates the stability of the karyotype of the studied horses.