CHROMOSOMAL PROFILE OF LARGE WHITE AND LAND BREED PIGS

Abstract

This article presents the results of studies of karyotypic variability of pigs of two breeds - large white and landrace.The research was carried out in the Department of Animal Genetics and Biotechnology of the Institute of Animal Breeding and Genetics named after M.V. Zubtsia of the National Academy of Sciences. Karyotype analysis was performed on preparations of metaphase chromosomes obtained from peripheral blood lymphocytes according to the generally accepted method. The following cytogenetic indicators were included in the analysis: the frequency of aneuploid and polyploid cells, the frequency of cells with structural aberrations of chromosomes. Statistical processing of experimental data was carried out using Office Excel 2003.A comparative analysis of the karyotypes of two groups of pigs of the Great White and Landrace breeds shows the statistical reliability of the difference between the experimental groups of pigs in terms of the frequency of aberrant cells.The spectrum of numerical violations of the karyotype in all groups is represented by poly- and aneuploid cells. A higher frequency of polyploid cells is observed in pigs of the landrace breed compared to individuals of the large white breed.Almost twice as many aneuploid cells were recorded in landraces than in large white pigs).Analysis of the karyotypes of the studied groups of pigs revealed various chromosomal aberrations - associations and translocations of chromosomes, chromosomal breaks and fragments. Chromosome breaks in both groups of examined pigs occur with the same frequency - almost 3%. In the karyotypes of individual sows, we found two different centric fusions of chromosomes: in sow No. 7659 of the landrace breed, a Robertsonian translocation of rob 15/17, and in sow No. 2817 of the Big White breed, an association of chromosomes 16 and 17. These pigs were diagnosed with a reduced level of reproductive capacity, the cause of which, obviously, is a violation of the separation of chromosomes in meiosis. Among the studied animals, we did not find individuals with reciprocal translocations.In our study, in landraces, the frequency of premature separation of the centromeric regions of chromosomes in mitosis is 35,5% more frequent than in individuals of a large white breed, which indicates an unbalanced genotype of the animals of this studied group and indicates the peculiarities of selection work with them.The analysis of the pedigrees of the sows that were selected in the group for this study confirmed this assumption: the animals were obtained by interbreeding.Almost twice the frequency of polyploid cells confirms their belonging to animals of the meat type of productivity.Therefore, the analysis of polymorphism of karyotypic traits of pigs of the two studied groups of pigs of the Great White and Landrace breeds shows that the cytogenetic parameters of the studied pigs vary in the following range: the frequency of aberrant cells - from 5.11±0.05 to 7.63±0.17; frequency of polyploid cells - from 4.50±1.6 to 7.84±2.6; aneuploid - from 3.0±1.8 to 5.6±2.9; the frequency of chromosome breaks is from 2.8±1.3 to 2.9±1.7. It is obvious that the level of chromosomal instability is dominated by landrace pigs, the reason for which, in our opinion, is the peculiarities of breeding work with this breed.