[Genetic processes and the problem of the target in chromosomal mutagenesis]

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