Cytogenetic analysis of breeding animals makes it possible to identify animals carrying cytogenetic abnormalities, the rate of spontaneous and induced somatic mutagenesis and the level of general genomic instability of animals. Scientists emphasize that in breeding work it is desirable to use animals whose offspring inherit high productivity and do not carry a genetic burden. The main factors that contribute to chromosomal instability are environmental factors, enzyme failure, changes in the system of repair or replication of chromosomes, suppression of immunity. It is important that the methods of breeding farm animals also have an impact on the stability of their karyotype. The appearance of deconsolidation of heredity and destruction of gene adaptive complexes during animal crossing has been established. This also applies to the use of related breeds, but obtained in different environmental conditions. As a result, aneuploidy, polyploidy may occur. It is proved that with the help of cytogenetic methods it is possible to establish new sources of genetic variability and prevent the spread of harmful chromosomal aberrations in animal populations. Such work was carried out on the Ukrainian brown dairy breed, created by crossing the local swan breed and related Swiss breed of American and European selections. That is, a related breed was used in its creation, but it had a difference in the selection system and ecological conditions of detention, which in turn may affect the stability of the karyotype of the new breed. The aim of our work was to study the variability of the karyotype of cows of the Ukrainian brown dairy breed. Materials and methods. Cytogenetic analysis, which was aimed at establishing the karyotype variability of Ukrainian brown dairy cows, was performed on biological material obtained from animals kept in the breeding plant of the State Enterprise "Research Farm of the Institute of Agriculture of the Northeast NAAS NAAS Sumy region. 15 cows were studied. Cytogenetic drugs were obtained from peripheral blood lymphocytes taken from the jugular vein using standard techniques. RPMI-1640 medium, bovine serum (preferably embryonic), antibiotic gentamicin, mitogen, a substance that stimulates mitotic division of lymphocytes in culture (phytohemagglutinin type P), were used to cultivate blood cells. The mixture was cultured in a thermostat at +37°C for 48 hours. Two hours before fixation, a solution of colchicine heated to 37°C at a final concentration of 0.3–0.5 μg/ml of culture medium was introduced into the culture. Freshly prepared 0.55% potassium chloride solution was used for hypotension. After hypotension, the culture was centrifuged, the supernatant was drained, and cooled to +4°C fixing fluid was added to the precipitate by mixing one part glacial acetic acid with three parts methyl (or ethyl) alcohol. The obtained preparations, after staining with the finished Giemsa dye, were analyzed for chromosomal variability under immersion magnification of the microscope by 1000 times and photographed. 100 metaphase plates were analyzed in each animal. The number of dinuclear lymphocytes (DJ), mononuclear lymphocytes with micronuclei (MJ), and mitotic index (MI) were counted on the same drugs. The frequency of DIA, IU, MI was calculated in ppm (number per 1000 cells). Analysis of karyotype variability of the studied animals showed the presence of quantitative and structural disorders of chromosomes. Quantitative disorders were detected in the form of aneuploidy, the average of which was 5.7%. Multiple chromosome enlargement (polyploidy) in the studied animals was not detected. The average value of asynchronous divergence of the centromeric regions of chromosomes was 0.5%. The limit of variability of ARCR in the studied cows was 0–5.0%, and structural chromosome abnormalities manifested themselves in the form of chromosomal breaks and amounted to 2.1%. According to the results of the micronucleus test, the proportion of lymphocytes with a micronucleus was 1.9‰, binuclear lymphocytes – 3.9‰, and the value of the mitotic index – 3.5‰. A positive relationship has been established between aneuploidy and ARCR, which are considered a prerequisite for chromosome loss; aneuploidy and mitotic index (P < 0.05), binuclear lymphocyte and mitotic index. A negative correlation was found between chromosome breakage and micronucleus lymphocyte. In animals of different blood levels according to the Swiss breed, chromosome set disorders in the form of aneuploidy were detected, the average values of which were 6.0 and 5.0%, respectively, which corresponds to the limit of spontaneous chromosomal variability. in the studied cows of brown dairy breed higher positive values were found between lymphocytes with a micronucleus and the duration of the service period and the interbody period. It was found that 43% of cows had stillborn calves during the life of the uterus with quantitative chromosome abnormalities (aneuploidy). In animals with undetected aneuploidy, only 25% of cows had stillborn calves during their lifetime. According to the results of cytogenetic testing of cows of the Ukrainian brown dairy breed of different linear affiliation, increased variability of the karyotype of animals of the Stretch line has been established. The results of the micronucleus test of brown dairy cows of different linear affiliation indicate the absence of mutagenic factors. Conclusions. Quantitative and structural chromosome disorders are characteristic of Ukrainian brown dairy cows. In animals of conditional blood status of 95% and more of the Swiss breed, the highest percentage of cells with aneuploidy (6.0%), the presence of asynchronous divergence of the centromere regions of chromosomes (0.63%) and chromosomal breaks (2.87%). According to the results of the micronucleus test, the cytogenetic parameters of cells (lymphocytes with a micronucleus, dinuclear lymphocytes and mitotic index) are 95% higher in animals of conditional blood status and more in the Swiss breed compared to animals of lower conditional blood status. karyotype (aneuploidy) on the percentage of stillbirth of calves and the proportion of lymphocytes with a micronucleus for the duration of the service and interstitial period. Differentiation of quantitative and structural chromosome disorders in brown dairy cows of different linear affiliation has been established. The fact of detection of chromosomal abnormalities indicates the need to significantly expand the scope of the survey of breeding stock, and especially in the leading breeding farms for the cultivation of Ukrainian brown dairy breed.

The purpose. Cytogenetic analysis of grey Ukrainian cattle and comparison of stability of its karyotype with retrospective data concerning animal breeds of different directions of productivity. Methods. Cytogenetic -analysis of metaphase plates of cells of peripheral blood of cattle; microkernel test, statistical. Results. The share of cells with aneuploidy at animals of grey Ukrainian breed made 1,2%; average arithmetical amount of aneuploidic cells at animals of breeds of milk direction of productivity -2,4%, that twice exceeded this index at grey Ukrainian cattle. At animals of breeds of the combined direction aneuploidy made 2%, at animals of breeds of meat direction of productivity -10,6% with statistically reliable variance (P>0,99). Variability on indexes of somatic polyploidy is not detected in cows of grey Ukrainian breed, share of 2-nuclear lymphocytes -2,2‰, that twice below, and mitotic activity of peripheral blood lymphocytes -2,8‰, that is authentically below (P>0,99) in comparison with the animals specified above. Conclusions. The karyotype of probed cows of grey Ukrainian breed was characterized by the heightened stability in comparison with animals of breeds of milk, combined and meat directions of productivity at spontaneous mutagenesis.

Brown Carpathian breed of cattle bred in Transcarpathia at the end of the XIX century. and belongs to the breeds of dairy and meat productivity. Animals of the modern breed are direct descendants of the ancient Brown Carpathian cattle, common at one time throughout Central Europe. The main advantage of the Brown Carpathian breed is that it can be effectively grown on natural pastures – both in the lowlands and in the mountains. The genetics of these animals are resistant to acute infectious diseases, they are well adapted to local conditions, sensitive to improved housing and feeding conditions, and cows produce special milk, which is used in the manufacture of high quality hard cheeses and baby food. Animals of the Brown Carpathian breed belong to the local small domestic breeds and are in a state of significant risk. The uterine population is bred only in households. The aim of our work was to study the karyotype variability of Brown Carpathian cows, which is quite relevant today. Cytogenetic analysis, which was aimed at establishing the karyotypic variability of Brown Carpathian cows, was performed in the village. Nyzhni Vorota, Volovets district, Zakarpattia region, in households. Purebred cows of Brown Carpathian breed – (16 heads) and local animals – (11 heads) were studied. According to the results of cytogenetic analysis, genomic disorders, aneuploidy, were found in purebred cows of Brown Carpathian breed, which was 1.6% and was expressed mainly by hypoploid cells 2n = 56–58. For domestic animals, the frequency of metaphase plates with aneuploidy was 3.3%, which corresponds to a spontaneous level of cytogenetic variability. Structural chromosome abnormalities, chromosomal breaks, in purebred cows were equal to 0.76%, which does not exceed the spontaneous level of chromosomal variability. In local animals, this variability did not manifest itsel. The indicators of the micronucleus test (the proportion of lymphocytes with a micronucleus of 1.7–2.0‰, dinuclear lymphocytes 1.5–2.7‰, and the mitotic index of 4.8–5.5‰, respectively) in domestic animals are higher compared to purebred animals, however, do not exceed those of the species Bos taurus. According to the results of the cytogenetic analysis, it was established that purebred cows of Brown Carpathian breed and their crossbreeds were characterized by quantitative and structural chromosome disorders. Genomic disorders, aneuploidy, in local animals are 2 times higher (3.3%) compared to purebred cows of Brown Carpathian breed with a statistically significant difference in mean values (P > 0.99). Low level or absence of structural disorders of chromosomes in purebred animals and their crossbreeds indicates a low degree of somatic mutagenesis. The indicators of the micronucleus test, as an indicator of the effect of the total mutagenic load on the body of the studied cows, in domestic animals are higher compared to purebred animals, however, do not exceed those characteristic of the species Bos taurus. It was established that the level of somatic mutagenesis is lower and the karyotype is more stable in purebred animals of the Brown Carpathian breed in comparison with the local ones.

Of the total dairy cattle, 49 % belong to the Ukrainian black-and-white dairy breed. Animals are demanding to the conditions of detention, so the aim of the study was to study the impact of seasonal changes in the environment on the stability of the karyotype of cows of three age groups (first-born, adult and cows 8–10 years). The variability of the karyotype of the studied animals in different seasons of the year was manifested in the form of quantitative and structural disorders of chromosomes. Of the total dairy cattle, 49 % belong to the Ukrainian black-and-white dairy breed. Animals are demanding to the conditions of detention, so the aim of the study was to study the impact of seasonal changes in the environment on the stability of the karyotype of cows of three age groups (first-born, adult and cows 8–10 years). The variability of the karyotype of the studied animals in different seasons of the year was manifested in the form of quantitative and structural disorders of chromosomes. In primiparous women, the most pronounced genomic variability (aneuploidy) was observed in summer and winter and was 16.4 % and 8.8 %. In summer, this variability was more than twice the limit of spontaneous chromosomal variability. The highest percentage of structural chromosome abnormalities (chromosomal breaks) in cows of three age groups was observed in winter and was 2.5 %, 2.8 %, 3.0 %, respectively, and did not exceed the limit of spontaneous mutagenesis characteristic of cattle. An increased proportion of lymphocytes with a micronucleus in first-borns and cows aged 8–10 years (5.6 ‰, 6.4 ‰, respectively) was observed in the summer. The increased proportion of dinuclear lymphocytes appeared in the first-born in the summer season and amounted to 7.6 ‰ (at P > 0.99), and in cows 8–10 years, this variability in the summer season was 6.2 ‰, in winter – 6.7 ‰ with a statistically significant difference (P > 0.95) between the spontaneous level of cytogenetic variability. The association between karyotype stability of the studied animals and seasonal environmental factors was determined using a correlation coefficient (r). A significant positive correlation was found between aneuploidy and air temperature in primiparous and cows aged 8–10 years, relative humidity, precipitation and wind strength and chromosomal gaps in primiparous and adult cows, atmospheric pressure, relative humidity and asynchronous divergence. in adult cows and cows aged 8–10 years. A positive reliable associative dependence of the appearance of micronucleus lymphocytes and dinuclear lymphocytes on the amount of precipitation and wind strength in this area in primiparous and adult cows was established.

The history of the origin and domestication of farm animals has always interested mankind. However, these issues are covered in the literature in great detail only from the time when herds of domestic animals have already formed. Most often, the genesis of individual species, the original forms that formed the basis of domestication, remain unclear. [2] An example is the history of domestication of the horse, as the horse played a central role among other domestic animals in the development of human society. In the study of mammal fauna of the Pleistocene-Holocene of Europe there is a problem of studying the origin of the domestic horse Eguus cabalus L., ie, the establishment of wild ancestors of domesticated breeds, place, time and process of their domestication. Analysis of literature data on paleontological and archaeological finds in Ukraine showed that most researchers believe that the first domesticated horses began to recognize horses, the remains of which were found during archaeological excavations of the settlement of the third millennium BC. BC in Botai (Northern Kazakhstan), but from which taxon the opinions of scientists differ. Some believe that it could be Tarpan, however, there is an opinion that a large horse could not come from a small tarpan and Przewalski's horse. Therefore, preference was given to the hypothesis of the origin of the domestic horse from the ancient Pleistocene. At present, the problem of the origin of the domestic horse does not go beyond hypotheses and assumptions, and this is primarily due to the slight difference between the bones of the domestic and wild horse. The plasticity of the skeleton of the genus Eguus is very weak and this explains the problems faced by paleontologists in trying to develop the evolutionary history of horses. Thus, to understand the processes of domestication of this animal, in addition to archaeological and paleontological research methods, it is necessary to use tools from other fields of science, such as molecular genetic analysis of DNA samples. One of the variants of test systems for studying genetic polymorphism is the use of ISSR markers, which allow to analyze DNA fragments and make certain phylogenetic connections in the studied groups. In the laboratory of genetics of the Institute of Breeding and Genetics of Animals named after M.V.Zubets NAAS began research in the field of paleogenetics, namely – the study of the molecular genetic component in the fossils of ancient members of the genus Eguus using ISSR-markers. Inverted repeats are of particular interest because they are unevenly distributed throughout the genome and do not require prior knowledge of the nucleotide sequence of the test DNA. A significant point in the selection of research methods for us was that intermicrosatellite polymorphism is used to study interspecific and intraspecific genetic variability. It is believed that DNA fragments obtained by ISSR analysis can be species- and breed-specific, and this method is widely used by researchers in the study of breed groups. The purpose of our work is to develop a new method of DNA isolation from fossil remains (bones) of ancient horses and the production of ISSR-PCR with isolated DNA samples in the laboratory of genetics IRGT. M.V.Zubets NAAS according to the available reagents and existing protocols. The research was carried out on samples of fossil bones of horses of the Pleistocene period (about 10 thousand years BC). One bone was found in the village. Beeches of Zhytomyr region in a career. Excavations were carried out in 1960, the metacarpal bone (os. Tarsicentral). Another bone was found in Novgorod-Siversky, Chernihiv region. in a career. Excavations were conducted by Boriskovsky PI in 1935. A tooth found in the village of Tarpan was used to study a wild tarpan horse (4.5 thousand years BC). Skibnytsia, Trostyanets district, Vinnytsia region. Excavations were conducted in 1959 by VM Danylenko. The paleontological material for the study was provided by the Kyiv National Museum of Natural History of the National Academy of Sciences of Ukraine, Department of Paleontology. As a result of this work for the first time in the Department of Genetics and Biotechnology IRGT. Research on paleogenetics has been started by M.V.Zubets. We optimized the method of extracting genetic material from fossils and obtained DNA from the bones of a horse of the Pleistocene period (about 10 thousand years BC) and the tooth of a wild horse tarpan (4.5 thousand years BC). Also, the optimal conditions for PCR were selected to work with DNA obtained from fossil remains, to study polymorphism with ISSR markers, and electrophoregrams of amplification products were obtained.