Theory of targets and problem of starting mechanisms of radiation mutagenesis of highest eukaryotes

N.V. Timofeev-Resovskiy, an outstanding radiobiologist and geneticist-evolutionist, played the most active role in the development of target theory and target-theory-base analysis of radiation mutagenesis starting mechanisms. Development of the concept on the connection between primary damage with finite genetic effect allowd the author to raise the problem concerning chemical nature of DNA premutation and preaberration modifications, which reflect essential canalization of modification initiation and realization at eukaryote genome hierarchically different levels (gene and chromosomal ones)