Intraspecific spontaneous chromosomal mutations in some rodents distributed in Azerbaijan, their induction by ionizing radiation and correction
Aim. Work is focused on the intraspecific spontaneous mutations of rodent chromosomes common in different regions of Azerbaijan, the effect of gamma radiation in doses 1 and 4 Gy on chromosomal aberrations in the bone marrow of rats pretreated with an extract from the collection of medicinal plants by injection was studied. Methods. The works on the study of chromosome morphology, changes in heterochromatic parts of chromosomes, chromosome regions of nucleoli formation, biometric processing of chromosomal aberrations. Results. Intrapopulational spontaneous chromosomal mutations in ordinary field mice in the Lesser Caucasus were registered. In normal karyotype chromosomes of fifth pair are presented by large subtelocentrics, while one chromosome of fifth pair in abnormal karyotype was heteromorphic and had acrocentric structure. Heteromorphic chromosomes differ in the heterochromatin composition as well. In the process of speciation are found mainly pericentric inversions, Robertson and tandem translocations. In metaphase plates along with chromosomal mutations were detected structural heterochromatin and nucleoli formation regions. Extract from the collection of medicinal plants was found to promote reduction of structural chromosome abnormalities as a result of radiation and ensures the normal functioning of cells. Conclusions. Spontaneous mutations in the fifth pair of chromosomes could be considered as the beginning of speciation, but recent studies in the Lesser Caucasus did not found individuals with this type of mutation. Microtus mayori karyotype demonstrated associations in nucleoli formation regions and it was suggested their mechanism.
Keywords: chromosome, wild mouse, extract, karyotype, radiation.