The fundamental goal of animal husbandry is the cost-effective production of human food from healthy animals, which includes production, reproduction. The method of whole-genome association study (GWAS) is actively used in various fields, including agriculture. Genome-wide association analyzes were generated as an identifier for genomic variations associated with economically significant traits in different livestock species. This method of genomic selection provides new priorities for improving the productive and reproductive qualities of livestock. The purpose of this review article is a comprehensive analysis of the current state of GWAS in cattle, focusing on the identification of SNPs associated with reproduction, productivity, growth, behavior and genetically determined diseases. The scope of the article covers the study of GWAS results worldwide, both in dairy and beef cattle, with special emphasis on the identification of candidate genes, QTL and genome regions related to the direction of productivity. Additionally, the organization of this review will include a classification of GWAS results based on the specific traits studied, providing a comprehensive overview of the genetic determinants of reproduction, growth, behavior, and disease traits in cattle.

У клинически здоровых коров голштинской породы (n=20) изучена динамика гормонального обмена в период глубокой стельности и после отела. У них в сыворотке крови определяли концентрацию кисспептина, 17β-эстрадиола и прогестерона. За животными вели регулярное наблюдение с проведением клинических и акушерско-гинекологических исследований. В зависимости от концентрации глюкозы и бета-гидроксимасляной кислоты на 5-й день после отела коров разделили на 2 группы: в I группу вошли 15 особей с концентрацией в крови глюкозы больше 3 ммоль/л и уровнем бета-гидроксимасляной кислоты ниже 1 ммоль/л. Во IIгруппе у 5 коров зафиксированы нарушения в энергообмене (глюкоза меньше 3 ммоль/л, и уровень бета-гидроксимасляной кислоты выше 1 ммоль/л). На 15-й день после отела была отмечена нормализация энергетического гомеостаза. Концентрация кисспептина в предотельный период в обеих группах снижалась к отелу. Его количество в крови животных в группе с нарушениями энергообмена было выше на 9, 7-й и 5-й дни до отела в 2,4—3 раза (P<0,01—0,05), по сравнению с I группой. Концентрация 17β-эстрадиола в предотельный период снижалась в обеих группах. Более высокое количество перед отелом зафиксировано во IIгруппе — в 2—3,2 раза больше, по сравнению с I групой (P<0,05). Уровень прогестерона к моменту отела повышался в крови животных обеих групп. Концентрация трех гормонов после отела резко снизилась. В дальнейшем существенных различий в концентрации кисспептина не зафиксировано, кроме 5-го дня после отела (P<0,05). Уровень 17β-эстрадиола в послеотельный период между группами достоверно различался в 1, 3, 5-й и 7-й дни (P<0,05). Более высокая концентрация после отела зафиксирована во II группе — в 2—2,4 раза. Уровень прогестерона в послеотельный период начал повышаться в I группе с 17-го дня после отела, а во II— с 11-го дня. Достоверные различия зафиксированы на 15, 17, 19-й и 21-й дни после отела (P<0,05). Полученные экспериментальные данные показывают, что кисспептин играет важную роль в адаптации к нарушениям в энергетическом обмене, которые наиболее явно проявляются у высокопродуктивных молочных коров во вторую половину транзитного периода при появлении отрицательного энергетического баланса. Дальнейшее уточнение концентраций кисспептина при фиксации уровня стероидных гормонов позволит раскрыть генез многих нарушений репродуктивной функции при отрицательном энергетическом балансе и его негативных последствиях. The dynamics of hormonal metabolism during deep pregnancy and after calving was studied in clinically healthy Holstein cows (n=20). The concentrations of kisspeptin, 17β-estradiol and progesterone were determined in their blood serum. The animals were regularly monitored with clinical and obstetric-gynecological studies. Depending on the concentration of glucose and beta-hydroxybutyric, acid, on the 5th day after calving, cows were divided into 2 groups: Group I included 15 animals with a blood glucose concentration of more than 3 mmol/l and a beta-hydroxybutyric acid level below 1 mmol/l. In group II, 5 cows showed disturbances in energy metabolism (glucose less than 3 mmol/l, and the level of beta-hydroxybutyric acid above 1 mmol/l). On the 15th day after calving, normalization of energy homeostasis was noted. The concentration of kisspeptin in the pre-calving period in both groups decreased towards calving. Its amount in the blood of animals in the group with energy metabolism disorders was higher on the 9th, 7th and 5th days before calving by 2.4—3 times (P<0.01—0.05), compared with group I. The concentration of 17β-estradiol in the prepartum period decreased in both groups. A higher concentration before calving was recorded in group II — 2—3.2 times (P<0.05). The level of progesterone at the time of calving increased in the blood of animals of both groups. The concentrations of the three hormones decreased sharply after calving. Subsequently, no significant differences in kisspeptin concentration were recorded, except on the 5th day after calving (P<0.05). Postpartum 17β-estradiol levels were significantly different between groups on days 1, 3, 5, and 7 (P<0.05). A higher concentration after calving was recorded in group II — 2—2.4 times. The level of progesterone in the post-calving period began to increase in group I from the 17th day after calving, and in group II — from the 11th day. Significant differences were recorded on the 15th, 17th, 19th and 21st days after calving (P<0.05). The experimental data obtained show that kisspeptin plays an important role in adaptation to disturbances in energy metabolism, which are most clearly manifested in highly productive dairy cows in the second half of the transit period when a negative energy balance appears. Further clarification of kisspeptin concentrations when fixing the level of steroid hormones will reveal the genesis of many reproductive dysfunctions with a negative energy balance and its negative consequences.

In recent years, genomic assessment and the widespread introduction of modern biotechnological techniques have played a leading role in the implementation of breeding programs. For a long time, increasing milk productivity has been the main goal of breeding. This led to a significant decrease in reproduction in herds. The reproductive indicators of the uterine livestock of cattle can largely reduce the total profitability due to additional costs for manual, veterinary assistance and forced culling. Experienced groups are genotyped using the Bovinesnp50 V3 Beadchip chip are formed from the cows of black-and-white holsteinized breed. For the study, the main reproductive traits of cows were chosen: the age of the first insemination, the insemination indices in front of the first (a), the second (b), the third (c), fourth (d) lactation and the period between hotels. Analysis of associations throughout the genome was carried out using EMMAX software. 2 significant SNP and 5 conditionally significant were found. The CAMK2D candidate gene with the age at the first insemination, the TLN2 , WSCD2 , GAPT genes with the indicator, the number of insemination and genes WDR36 , TDRD10 with the inter -suffering period was identified. Based on the studies, we assume that with age there is a change in the genetic factors affecting animal fertility. The identified candidate genes affect the mechanisms of maturation of follicles, so the growth and development of embryos. The results can be used both for the selection of animals to improve reproduction indicators, and for the search for the fundamental foundations of the formation of fertility in cattle.

Today, poultry farming is a highly efficient branch of animal husbandry, and the domestic chicken (Gallus gallus) is the most common type of farm animals. Significant changes in the exterior of chickens reflect the acquired biological characteristics of the bird and are closely related to the formed direction of productivity. The article is devoted to the comparison of the exterior profiles of two domestic chicken breeds of different productivity directions: Russian White (egg), Tsarskoye Selo (meat and egg). Exterior assessment occupies an important place in the grading of breeding poultry.As a result of the study, it was revealed that the body structure of Tsarskoye Selo chickens meets the requirements of a heavy bird with good meat qualities. In comparison with Tsarskoye Selo chickens, Russian White chickens have a more developed abdominal part, in which the egg-forming organs are located. This is confirmed by a significantly smaller difference in the pelvic width (only 0.81 cm). In addition, the Russian White breed of chickens had a high index of legginess — 53.5, compared to the index value of 21.1 for the Tsarskoye Selo breed. The index of latitudinal proportionality for the Tsarskoye Selo breed of chickens is 2 times higher (94.0), which also indicates its productivity direction (meat and egg). Detailing and specifying breeds according to exterior indicators helps in approving new breeding forms of the State Commission of the Ministry of Agriculture.

The worldwide chicken gene pool encompasses a remarkable, but shrinking, number of divergently selected breeds of diverse origin. This study was a large-scale genome-wide analysis of the landscape of the complex molecular architecture, genetic variability, and detailed structure among 49 populations. These populations represent a significant sample of the world's chicken breeds from Europe (Russia, Czech Republic, France, Spain, UK, etc.), Asia (China), North America (USA), and Oceania (Australia). Based on the results of breed genotyping using the Illumina 60K single nucleotide polymorphism (SNP) chip, a bioinformatic analysis was carried out. This included the calculation of heterozygosity/homozygosity statistics, inbreeding coefficients, and effective population size. It also included assessment of linkage disequilibrium and construction of phylogenetic trees. Using multidimensional scaling, principal component analysis, and ADMIXTURE-assisted global ancestry analysis, we explored the genetic structure of populations and subpopulations in each breed. An overall 49-population phylogeny analysis was also performed, and a refined evolutionary model of chicken breed formation was proposed, which included egg, meat, dual-purpose types, and ambiguous breeds. Such a large-scale survey of genetic resources in poultry farming using modern genomic methods is of great interest both from the viewpoint of a general understanding of the genetics of the domestic chicken and for the further development of genomic technologies and approaches in poultry breeding. In general, whole genome SNP genotyping of promising chicken breeds from the worldwide gene pool will promote the further development of modern genomic science as applied to poultry.

In the clinically healthy cows of the Holstein breed (n = 20), a hormonal background was studied during theperiod of deepness and after the edema. For this purpose, the concentration of kisspeptin, testosterone and cortisol was determined in serum cows in the blood cows. The animals conducted regular observation with the conduct of clinical and obstetric and gynecological studies. Depending on the concentration of glucose and beta-hydroxybutyric acid on the 5th day after calving, the cows were divided into two groups. The first group included 15 heads with a glucose concentration greater than 3 mmol/l and a beta-hydroxybutyric acid level below 1 mmol/l. In the second group, 5 heads had violations in energy exchange (glucose levels less than 3 mmol/l, beta-hydroxybutyric acid above 1 mmol/l). On the 15th day after the hotel, normalization of energy homeostasis was recorded. The concentration of kisspeptin in the preventive period in both groups decreased to the hotel. At the same time, the concentration of kisspeptin in the blood of animals in the group with energy exchange disorders was 2.4–3 times higher on the 9th, 7th and 5th days before calving (p < 0.01–0.05) compared with the first group. In production experience, the concentration of all three hormones after the hotel decreased with significant intergroup differences. The level of kisspeptin was reliably higher in the preventive period in the experimental group and on the 5th day after the hotel (p < 0.05). The cortisole level was held at a high level of up to 7 days after the hotel (p < 0.05). The concentration of testosterone in the blood throughout the transit period was reliably high in the animals of the experimental group.

In clinically healthy Holstein cows (n=25), the dynamics of hormonal metabolism in the first trimester of cow pregnancy was studied. For this purpose, the concentration of kisspeptin, 17β-estradiol, progesterone and cortisol was determined in the blood serum of cows. The animals were regularly monitored with clinical and obstetricgynecological studies. The level of kisspeptin in the first trimester of pregnancy increased almost throughout the entire period under consideration with a decrease in concentration to 194.23±23.61 pg/ml on day 98. The level of estradiol during the first trimester increased from 49.66±9.68 to 76.20±17.84 pg/ml, respectively, which is also explained by the inclusion of the fetoplacental complex in its synthesis and secretion. Progesterone and cortisol levels were on average at the same level. During the experiment, out of 25 animals, embryonic death was recorded in 14 on the 30th day after insemination. As a result, two groups were formed: the 1st group - animals with a normal course of pregnancy and the 2nd group with embryonic death. Analyzing the data of enzyme immunoassay in animals of the 1st group, one can note a decrease in the level of kisspeptin by 11% on the 28th day compared to the 14th day after insemination. At the same time, the concentration of estradiol, on the contrary, increased by 29%. In the second group, on the contrary, the level of kisspeptin and estradiol did not change and, on average, remained almost at the same level. On the 28th day after insemination in the first group, the cortisol concentration was significantly higher compared to the second group - 15.32±3.23 and 9.00±0.89 nmol/l, respectively. Data for kisspeptin and estradiol showed no significant differences. However, it is of interest that in the first group, with an increase in the level of estradiol, a decrease in the level of kisspeptin occurs. In particular, this is consistent with previous studies, according to which such an interaction of these hormones can be regulated by a high concentration of progesterone.

У клинически здоровых коров голштинской породы (n=10) изучена динамика гормонального обмена в лютеиновую фазу полового цикла. С этой целью у коров в сыворотке крови определяли концентрацию кисспептина, 17β-эстрадиола и прогестерона. За животными вели регулярное наблюдение с проведением клинических и акушерско-гинекологических исследований. В зависимости от индекса осеменения коров разделяли на две группы: 1-ая группа: с индексом осеменения более 1 и 2-ая группа — равным 1. Уровень прогестерона в ходе лютеиновой фазы увеличивался, и концентрация в исследуемых группах практически совпадала: в 1-й группе — 8,56±0,92, во 2-ой — 8,94±0,74 нг/мл. Уровень 17β-эстрадиола в группе животных с индексом осеменения более 1 был ниже в сравнении со 2-ой группой — на 10-ый день лютеиновой фазы зафиксировано достоверное различие (P<0,05). Уровень кисспептина показал противоположную динамику. В группе коров с индексом осеменения 1 уровень кисспептина был достоверно ниже на 12-ый и 16-ый дни лютеиновой фазы (P<0,05). Наши исследования показывают схожую динамику по кисспептину и 17β-эстрадиолу в каждой группе животных. При этом в определенные дни лютеиновой фазы наблюдалось расхождение — при повышении уровня 17β-эстрадиола понижалась концентрация кисспептина и наоборот. В группе животных с индексом осеменения более 1 это отмечено с 8 по 12 день лютеиновой фазы, во 2-ой группе — с 10 по 14 день. Затем динамика вновь становилась схожей. Причина такого разобщения пока неясна и требует дополнительных исследований. In the clinically healthy cows of the Holstein breed (n = 10), the dynamics of hormonal metabolism in the luteal phase of the estrous cycle have been studied. To this end, the concentration of kisspeptin, 17β-estradiol and progesterone was determined in serum cows in serum cows. The animals conducted regular observation with the conduct of clinical, obstetric, and gynecological studies. Depending on the insemination index, the cows were divided into two groups: the 1st group: with the insemination index of more than 1, and the 2nd group with the insemination index 1. The level of progesterone during the luteal phase increased, and concentration in the studied groups almost coincided: in the first group - 8.56 ± 0.92, in the second - 8.94 ± 0.74 ng/ml. The level of 17β-estradiol in the group of animals with an insemination index of more than 1 was lower in comparison with the second group-on the 10th day of the lutein phase, a reliable difference was recorded (p <0.05). The level of Kisspeptin showed the opposite dynamics. In a group of cows with an insemination index 1 level of kisspeptin was reliably lower for the 12th and 16th days of the luteal phase (p <0.05). Our studies show similar dynamics by kisspeptin and 17β-estradiol in each group of animals. At the same time, on certain days of the lutein phase, a discrepancy was observed-with an increase in the level of 17β-estradiol, the concentration of kisspeptin and vice versa. In a group of animals with an insemination index of more than 1, this is noted from the 8th to 12th day of the lutein phase, in the second group - from 10 to 14 days. Then the dynamics again became similar. The reason for such a division is still unclear and requires additional research.

The aim of the study was to analyse the association of polymorphic variants of the LCORL gene for SNP A503G with egg quality in chickens of the Pushkin and Tsarskoye Selo breeds. The sample consisted of chickens of the combined productivity direction of the Pushkin (n=107) and Tsarskoye Selo (n=90) breeds of 2021 year of hatching. The birds were kept in individual cages on the basis of the bioresource collection of the RRIFAGB “Genetic Collection of Rare Endangered Breeds of Chickens” (Pushkin, St. Petersburg). The poultry were genotyped by PCR-RFLP. Biophysical properties of the eggs were evaluated in hens at 35 weeks of age. A comparative analysis of the qualitative characteristics of the eggs revealed some differences between the breeds. For examle, the eggs from the Pushkin breed hens differed from the eggs of the Tsarskoye Selo hens in high egg weight (p ≤ 0.001) and shell (p ≤ 0.01), shell thickness (p ≤ 0.01), PPF values (p ≤ 0.01), but had a thinner shell membrane (p ≤ 0.01). The analysis of the SNP A503G association with the LCORL gene showed that the eggs from the Pushkin chickens with the AG genotype had high mean values for shell thickness (p < 0.001), shell weight (p < 0.05) and yolk weight (p < 0.01). For chickens of the Tsarskoye Selo breed, significant associations were obtained for chickens with the AG genotype on the basis of yolk weight (p ˂ 0.05).

In meat-type poultry breeding, pectoral angle (PA) is a conventional anatomical indicator for changes in body conformation and meat traits; its correlation to egg performance is however deemed controversial. In this context, we revisited, assessed and put forward evidence for the usefulness of this classic phenotypic variable and its specific integrative index of pectoral angle-to-body weight ratio (PA/BW). Specifically, we identified respective correlations and used them for distinguishing the major categories (production types) of diverse chicken breeds under the traditional classification model (TCM) and genotypic clustering models of the global chicken gene pool subdivision. Also, the usefulness of the supplementary integrative egg mass yield index (EMY) for this objective was demonstrated. Because of estimating the total mass of eggs laid (i.e. egg number times egg weight), EMY can serve as an indicator of egg production. Direct approximation of EMY values by PA and BW values did not lead to significant correlation dependences between these indicators in each of the four breed utility types according to TCM. However, using the ratio of PA to BW, instead of PA and BW alone, resulted in significant correlation of EMY with PA/BW, allowing for distinction between egg-type and non-productive breeds. The validity of the proposed correlation-based models was supported by PCA and Neighbor Joining clustering analyses. Collectively, we suggested that PA can be a potentially correlated trait for selecting hens and roosters in breeding flocks to boost egg yield. These results can also be applied to chicken breeding as well as conservation- and phenome-related research.

The aim of the study is to select and test test-systems for SNPs in the LCORL-NCAPG locus, to study their relationship with exterior indicators in Pushkin chickens.

Divergently selected chicken breeds are of great interest not only from an economic point of view, but also in terms of sustaining diversity of the global poultry gene pool. In this regard, it is essential to evaluate the classification (clustering) of varied chicken breeds using methods and models based on phenotypic and genotypic breed differences. It is also important to implement new mathematical indicators and approaches. Accordingly, we set the objectives to test and improve clustering algorithms and models to discriminate between various chicken breeds. A representative portion of the global chicken gene pool including 39 different breeds was examined in terms of an integral performance index, i.e., specific egg mass yield relative to body weight of females. The generated dataset was evaluated within the traditional, phenotypic and genotypic classification/clustering models using the k-means method, inflection points clustering, and admixture analysis. The latter embraced SNP genotype datasets including a specific one focused on the performance-associated NCAPG-LCORL locus. The k-means and inflection points analyses showed certain discrepancies between the tested models/submodels and flaws in the produced cluster configurations. On the other hand, 11 core breeds were identified that were shared between the examined models and demonstrated more adequate clustering and admixture patterns. These findings will lay the foundation for future research to improve methods for clustering as well as genome- and phenome-wide association/mediation analyses.

An appreciation of the synergy between genome and phenome of poultry breed is essential for a complete un-derstanding of their biology. Phenotypic traits are shaped under the influence of artificial, production-oriented, selection that often acts contrary to that which would occur during natural selection. In this comparative study, we analysed the phenotypic diversity of 39 chicken breeds and populations that make up a significant part of the world gene pool. Grouping patterns of breeds found within the traditional, phenotypic models of their classifi-cation/clustering required in-depth analysis using sophisticated mathematical approaches. As a result of studying performance and conformation phenotypes, a phenomenon of previously underestimated variability in pectoral angle (PA) was revealed. Moreover, patterns of PA relationship with productive traits were analysed. We propose using PA measurement as a promising new auxiliary index for selecting hens and roosters of breeding flocks in egg production improvement programs.

Obtaining productive animals, including chickens, with specified characteristics is a promising area of modern animal husbandry. The most relevant traits for chickens are increased meat and egg productivity, resistance to infectious diseases, products with reduced allergenicity, and the production of integrated transgenic proteins. The rapidly developing methods of molecular genetics, such as genome editing, allow for solving these problems. In birds, unlike mammals, access to the unicellular zygote—when editing the genome is most effective—is difficult due to the special structure of the reproductive system. As a result, innovative methods have been developed for genetic engineering of birds, the most common of which is the use of primordial germ cells (PGC), precursors of poultry reproductive cells. This review provides a brief description and discussion of modern methods of editing the chicken genome using endonucleases, such as transcription activator-like effector nucleases (TALEN) and the system of clustered short palindromic repeats CRISPR/Cas9. Particular attention is paid to methods of gene editing in birds using primordial germ cells (PGC). Various strategies for the delivery of guide RNA (gRNA) and Cas9 protein into poultry cells based on the use of plasmid vectors, an alternative method of delivery of genetic constructs using spermatozoa (STAGE), the RNP method, which consists in direct delivery of gRNA and Cas9 protein in the form of a complex ribonucleoproteins, and the RNP method based on the use of nanobubbles were considered.

Using SNP analysis, genomic variation of the NCAPG-LCORL locus in chickens of 49 gene pool breeds and crossbreds from the Genetic Collection of Rare and Endangered Chicken Breeds was analyzed. Genotyping was performed using an Illumina Chicken 60K SNP iSelect BeadChip. As a result of SNP scanning, five significant SNPs were identified in the NCAPG-LCORL region in all breeds and crossbreds of the analyzed groups of chickens for GGA4. Cluster analysis of admixture models revealed a subdivision of individuals according to their origin at K = 5. Chickens of the egg and meat types formed two separate clusters, which is consistent with the results of genotype frequencies. When analyzing genetic differentiation between groups of chickens with different utility types on the basis of pairwise FST values, significant differences (p < 0.05) were found for the group of egg-type chickens in comparison with meat-type (0.330), dual purpose (meat-egg, 0.178), game (0.225 ) and dual purpose (egg-meat, 0.237) chickens, as well as for meat-type relative to fancy chickens (0.153). The results showed that the compared groups differ genetically from each other, which is confirmed by the data on genotype frequencies. The population specificity of the linkage disequilibrium structure at the NCAPG-LCORL locus was revealed for 11 chicken breeds. В ходе исследования с помощью анализа однонуклеотидного полиморфизма (SNP) была проанализирована геномная изменчивость локуса NCAPG-LCORL у кур 49 генофондных пород и гибридных форм из «Генетической коллекции редких и исчезающих пород кур». Генотипирование проводили с помощью чипа Illumina Chicken 60K SNP iSelect BeadChip. В результате SNP-сканирования у всех пород и гибридов анализируемых групп кур на GGA4 в регионе, включающем NCAPG-LCORL, и в области рядом с этим регионом определено пять значимых SNPs, которые могут быть кандидатами для селекции с помощью маркеров (MAS). Кластерный анализ адмикс-моделей обнаружил разделение особей соответственно их происхождению при К=5. Куры яичного и мясного направления продуктивности сформировали два обособленных кластера, что согласуется с результатами частот генотипов. При анализе генетической дифференциации между группами кур различного направления продуктивности на основе попарных FST-значений отмечены достоверные различия (p < 0,05) для группы кур яичного направления продуктивности в сравнении с мясными (0,330), мясо-яичными (0,178), бойцовыми (0,225) и яично-мясными (0,237), а также для кур мясного направления продуктивности относительно декоративных (0,153). Результаты показали, что сравниваемые группы отличаются генетически друг от друга, что подтверждается данными о частотах генотипов. Выявлена популяционная специфичность структуры неравновесия по сцеплению (LD) по локусу NCAPG-LCORL для 11 пород кур.

Obesity of chickens significantly reduces the efficiency of feeding, egg production, palatability of meat carcasses, slaughter yield, consumer value, and there is also such an ecological aspect as the problem of fat utilization. The search for SNPs in genes involved in lipid metabolism is an important task today for modern research in the field of poultry farming. Differences in carcass fat between breeds and lines within a breed illustrate the importance of genetic factors in lipid metabolism in chickens. The aim of the study was to find and analyze SNPs in the PPARG gene by sequencing in various chicken breeds (n = 83). The objects of the study were chickens from the VNIIGZh bioresource collection "Genetic collection of rare and endangered chicken breeds" (Pushkin, St. Petersburg) of various productivity trends (n = 83). Blood for DNA isolation was taken from hens at the age of 330 days from a wing vein into a microtube containing 50 μl of 0.5 mM EDTA as an anticoagulant. Prior to use, blood samples were stored at -200C. Genomic DNA was isolated using a standard phenolic-detergent method. The concentration and purity of the samples were determined using a NanoDrop 2000 instrument (Thermo Fisher, USA).Analysis of the polymorphism of the regulatory region of the PPARG gene was carried out by sequencing. The primer design was carried out on the basis of information from the Internet database.The studies were carried out on the basis of the laboratory of molecular genetics of the RRIFAGB. Genetic variability for rs314476701 of the PPARG gene was determined in the analyzed breeds. SNP rs316237745 revealed a strong shift of the A.

Along with the genetic characteristics of various poultry breeds, it is required to pay sufficient attention to the study of their phenotypic traits. We analyzed in a comparative aspect the phenotypic diversity of 39 chicken breeds and populations that make up a significant portion of the world gene pool. Breed grouping patterns found within the traditional model of their classification require further analysis using more sophisticated mathematical approaches. Наряду с генетической характеристикой различных пород птиц, требуется уделять достаточное внимание изучению их фенотипических признаков. Нами проанализировано в сравнительном аспекте фенотипическое разнообразие 39 куриных пород и популяций, составляющих значительную часть мирового генофонда. Паттерны группирования пород, обнаруженные в рамках традиционной модели их классификации, требуют дальнейшего анализа с использованием более сложных математических подходов.