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.

The article presents the results of molecular genetic studies performed on samples of biological material from ancient horses (DNA was isolated from fossils of Pleistocene horse and tarpan) and three aboriginal breeds of modern horses (Polish horse, Hutsul breed, Arabian breed). The research was conducted in the laboratory of genetics IRGT. M.V.Zubets NAAS. Purpose of research. This work was carried out to compare the effectiveness of each of the ISSR-markers and then select the optimal combination in the study of polymorphism of the genetic structure of horses To study the DNA polymorphism of horses on ISSR markers, we used eight primers that are considered the most informative (AG)8CA, (AG)9C, (GA)6CC, (GA)9C, (AG)8CG, (GAG)6C, (ACC)6G, (CTC)6C. Research methods. DNA from the blood was isolated using a set of reagents "DNA sorb B". From fossil remains of horses, DNA was isolated by an optimized method using proteinase K and dithiothreitol. The PCR mixture contained: 1 μl of buffer for Tag polymerase, 1 μl of a mixture of triphosphates ("Amplisens", RF), 0.8 μl of the appropriate primer, 0.2 μl of DNA polymerase ("Fermentas", Lithuania), water for PCR 3 μl. Genomic DNA was added in an amount of 4 μl. The total volume of the DNA mixture was 10 μl. Amplification was performed on a programmed four-channel thermocycle "Tertsyk" ("DNA technology", Russia). The amplification program included primary denaturation (95°C, 2 min); 30 cycles of denaturation (95°C, 30 s), hybridization of primers (54–64°C, 30 s) and elongation (72°C, 1 min), finishing elongation (72°C, 5 min). To more accurately estimate the lengths of the detected amplification fragments, a universal scale was used, where the gradation of DNA fragments by molecular weights was used. Depending on the zone ("heavy", "medium" and "light" fragments), a certain step from 10 to 200 bp was used. As a result, 38 zones with a fixed interval were identified, which allow to accurately determine the molecular weight for amplification products of different lengths and standardize the results of this study. Obtained results and conclusions. In the study of the obtained spectra of amplification products, we found that the largest number of loci was obtained by using as primers the sequences (GA) 6CC and (GAG) 6C – 9 and 8 loci. At the same time, primers (AG) 8CA – 0.27, (AG) 9C – 0.21 and (ACC) 6G – 0.21 were the most polymorphic in terms of PIC. It should be noted that when using primer (GA) 6CC in the study of genetic polymorphism of horses was obtained a significant range of amplification products – 9 loci, with a polymorphism index of 0.16, which allows it to be used quite effectively for research. Using the sequence (AG) 8CG was characterized by the lowest PIC index and was 0.02. As a result, we found that the most effective for the detection of polymorphism in the PIC index in horses was the use of primers sequences (AG) 8CA, (AG) 9C, and (ACC) 6G. To obtain the largest range of amplification fragments in horses by ISSR-PCR, the most effective was the use of the sequence (GA) 6CC and (GAG) 6C.

Introduction. The study of the genetic structure of the goat population by candidate genes associated with indicators of animal development and milk productivity is a promising direction, because the developing industry requires the introduction of advanced research methods. The use of methods of molecular genetic analysis can supplement breeding work to create optimally productive herds. In this connection, research is actively being conducted to study the influence of milk protein and hormone gene polymorphisms on milk productivity. Materials and methods of research. This work was carried out as a search for molecular genetic markers of productive traits in goat breeding, based on research in the world scientific literature on this topic. Research results. Goat breeding is an important branch of world animal husbandry. Goats are bred in all parts of the world, but the distribution of breeds in terms of productivity varies depending on the consumption tradition. For example, Europe is characterized by a predominance of dairy breeds, in Asia combined breeds, and in Africa meat breeds of goats are most often bred. The largest population of goats is kept in Asia and Africa. Significant producers of goat milk in the world are India, Bangladesh, Pakistan and Sudan. Global production of goat meat has increased by 41.66% over the past few years. Asia has the largest contribution to total meat production (70.7%). The leader in meat production is China, which produces 35.89% of goat meat from the entire world production. Goat breeding is widespread due to the ability of small cattle to easily adapt to different management systems and the ability to adapt to various climatic conditions and features of the terrain. A review of the world scientific literature confirms the fact that countries with significant demographic growth are most interested in selection work in goat breeding, taking into account genotyping by allelic variants of candidate genes for productive traits. Conclusions. As a result of the work, two proteins associated with quality indicators of milk were selected as candidate genes for productive traits: kappa-casein and beta-lactoglobulin, and two hormones that indirectly affect the growth and development of animals: leptin and somatotropin. The article briefly describes their functions in the body and the localization of the corresponding loci in the genome of animals. These markers are widely used for researching populations of cattle, goats and sheep in the world. This search for molecular genetic markers is aimed at carrying out similar studies in Ukraine to promote selection work in goat breeding.