Genetics - A. V. Sivolob 2008

The Nature of Genetic Material
DNA Repair

DNA Repair is a fundamental biological process aimed at correcting DNA Synthesis errors during Replication, as well as the numerous forms of damage induced by chemical and physical agents. Such damage includes various chemical modifications of nitrogenous bases, covalent cross-linking of adjacent Pyrimidines (resulting in The formation of pyrimidine dimers, most commonly thymine dimers) triggered by ultraviolet radiation, single- and double-strand breaks caused by ionizing radiation and free radicals, and more. Repair systems frequently operate during or immediately following replication. While most repair pathways involve the excision of the damaged single-stranded segment followed by DNA synthesis via DNA polymerases, certain mechanisms achieve the direct "correction" of the damaged site through the immediate action of specific Enzymes (Direct Repair).

No DNA repair system is 100% efficient; a fraction of lesions inevitably persists in the DNA, leading to nucleotide substitutions, sequence deletions, and other disruptions of the hereditary program known as Mutations (for a detailed Structure/133.html">Discussion on the Variability of Genetic Material, see Chapter 4). Naturally, impairments in DNA repair systems result in an elevated mutation rate, thereby accelerating the Mutational Process.



Last update: 11/08/2026

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