S u m m a r yBy a hybridization of wild and domestic sheep, a gene fond of sheep breeds can be enriched with useful traits, and the rare and disappearing species reconstructed. In our experiments, the hybridization between Ovis nivicola borealis and O. ammon ammon resulted in a reproductive offspring. The parental and hybrid animals were compared as to their karyograms which were determined on the base of ideogram for goats with addition of metacentric chromosomes. The cytogenetic data and the reproductive state of the hybrid confirm that the taxa used in hybridization are closely related.

A b s t r a c tConservation of biodiversity is one of the global challenges of the modern world. The preservation of animal genetic resources is considered essential for the food supply, since sustainable food production appears to be the greatest problem due to the human population growth, depletion of the Earth's natural resources, and many species becoming endangered. In situ and ex situ methods of preservation of the species (i.e. in/out of their natural habitats, respectively) are two major approaches to animal biodiversity conservation. Ex situ strategy involves the techniques for the genetic material cryopreservation. Cryopreservation of the wildlife biomaterials allows to use these genetic resources not only for the conservation and the renewal, but also for the introduction into the genotype of the farm animals. The bison (Bison bonasus) is identified as the rare and endangered species. At present, the free-living bison population in Russia comprises more than 1500 animals. A research concept of the Russian bison gene pool preservation includes creating cryo-preserved pool of bison spermatozoa. In this paper we report findings on biological adequacy of the cryopreserved epididymal bison semen after the long storage (for more than 20 years). The sperm samples were collected postmortem from the testicular appendages of four bison males sustained the injuries incompatible with life or culled and used for hunting. For the assessment of semen motility we used a computerassisted semen analysis (CASA) device; the DNA fragmentation index was assessed in AO-test with the acridine orange staining. The acrosomal integrity was studied by Diff-Quik staining method. It was shown that the semen quality parameters differed significantly due to the individual peculiarities of the bison. The spermatozoa of A + B grade which performed good motility and rectilinear motion reached more than 28 % in the semen of the males Mutfil and Morus, while in the Avel's and Misir's semen over 67 % spermatozoa were non-motile and 12.1 % and 10.4 % spermatozoa exhibited rotational and vibrational motions, respectively. The frequency of spermatozoa with pathomorphological changes significantly varied depending on the individual properties of the bison, with the greatest and the lowest values of 14.6 % and 6.8 %, respectively. The DNA fragmentation index reflecting sperm chromatin integrity can depend on the numerous biotic and abiotic factors and may vary in great ranges. In our surveys, it varied from 7 % to 86 %. For all the morphometric parameters, except the head width, the bison spermatozoa were inferior to the spermatozoa of the bulls though the differences between animal groups were not statistically significant. However, the area of the spermatozoa head in bulls was 3.14 m 2 larger than that of bison.

Despite their economic value, sheep remain relatively poorly studied animals in terms of the number of known loci and genes associated with commercially important traits. This gap in our knowledge can be filled in by performing new genome-wide association studies (GWAS) or by re-analyzing previously documented data using novel powerful statistical methods. This study is focused on the search for new loci associated with meat productivity and carcass traits in sheep. With a multivariate approach applied to publicly available GWAS results, we identified eight novel loci associated with the meat productivity and carcass traits in sheep. Using an in silico follow-up approach, we prioritized 13 genes in these loci. One of eight novel loci near the FAM3C and WNT16 genes has been replicated in an independent sample of Russian sheep populations (N = 108). The novel loci were added to our regularly updated database increasing the number of known loci to more than 140.

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Negative heterosis can occur on different economically important traits, but the exact biological mechanisms of this phenomenon are still unknown. The present study focuses on determining the genetic factors associated with negative heterosis in interspecific hybrids between domestic sheep (Ovis aries) and argali (Ovis ammon). One locus (rs417431015) associated with viability and two loci (rs413302370, rs402808951) associated with meat productivity were identified. One gene (ARAP2) was prioritized for viability and three for meat productivity (PDE2A, ARAP1, and PCDH15). The loci associated with meat productivity were demonstrated to fit the overdominant inheritance model and could potentially be involved int negative heterosis mechanisms.

Study of individual cell morphemes in animals has fundamental and applied meaning. The principle issue of modern biology is mechanistic study of functioning and cooperation of nucleus cell structures. Real interest is in- depth study of nucleus cell structure, connected with proliferative and synthetic cell activity in animals. Parts of chromosomes contain specialized structures- so called nucleolar organizers (NOR). Number of these subunits polymorphous and depends on complex of factors. Principle facto , influencing the number of NOR, is a specific accessory and individual features of the body. In NOR zone genes of 2 classes of rRNA: 18S and 28S, which are in ribosomes, taking part in their functioning. NOR perform functions in cells, take part in protein secretion. The aim of this survey is the analysis of NOR polymorphism in domestic and farm animals and identifying economic traits with polymorphism and NOR structure. According to NOR we can implicitly estimate activity of synthesis of ribosomal RNA and distinguish cell- doubling capacity and state of cell differentiation. Metaphase NOR are used as indicator of physiological and productive body state. Cytogenic assays, aimed to study intraspecific animal variety, are carried out on the basis of localization in NOR cells.

The aim of this study is to identify the effects of progesterone (PRG) on the capacitation and the acrosome reaction in bovine spermatozoa. The fresh sperm samples were incubated with and without capacitation inductors (heparin, dibutyryl cyclic adenosine monophosphate (dbcAMP)), hormones (prolactin (PRL), PRG), inhibitors of microfilaments (cytochalasin D) and microtubules (nocodazole) during capacitation and acrosome reactions. The functional status of spermatozoa was examined using the chlortetracycline assay. Supplementation of heparin stimulated capacitation in the presence and absence of PRG. Cytochalasin D blocked the stimulating effect of heparin on capacitation. The addition of PRL during capacitation (without PRG) did not affect the functional status of spermatozoa, while in PRG-treated cells PRL stimulated the acrosome reaction. PRL (with and without PRG) increased the acrosome reaction in capacitated cells. These PRL-dependent effects were inhibited by nocodazole. During the acrosome reaction, in presence of dbcAMP, PRG decreased the proportion of acrosome-reacted cells compared to PRG-untreated cells. This effect in PRG-treated cells was canceled in the presence of nocodazole. In conclusion, PRG under the action of PRL and dbcAMP determines the changes in the functional status of native sperm cells, which indicates PRG modulating effect on the indicators of post-ejaculatory maturation of spermatozoa.

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