A brief review of studies performed in the Department of Genetics of St. Petersburg University by M.E. Lobashev and his disciples is presented. The results of these studies prove that the formation of a mutation is a multistage process involving many cell and organism systems (including repair systems, systems that determine sexual dimorphism, etc.), which are affected by environmental factors (e.g., extreme temperatures). They can hinder or accelerate the mutational process, in this way providing both a superadditive effect and adaptive response. Recent studies deal with a universal system of heat shock proteins, which is involved in the maintenance of resistance of genetic material and genetic processes in the cell.