The general mechanism of chromosomal mutagenesis: basic and applied aspects

Based on the analysis of literature and the findings of the present work, it is assumed that there are two main mechanisms of formation of structural chromosome mutations in eukaryotic cells: 1) homologous recombinations, resulting in the formation of all kinds of chromosome exchanges; 2) the process of telomere formation, resulting in the generation of true deletions. Some chromosome breaks registered in the first K-mitosis of cells after exposure to mutagens reflect temporary disturbance of chromatin condensation. These aberrations can be repaired in the next nuclear cycle. Data are presented that argue in favour of the existence of a minor fraction of DNA sequences that serve as the molecular basis of specific targets of chromosome mutagenesis. These sequences can play an essential role in the normal structural and functional organization of the nucleus.