Thus, understanding the cellular responses to ionizing radiation constitutes a major goal in biomedical research. DSBs are also intermediates of normal cellular processes like DNA replication, meiosis, and immunoglobulin rearrangement. A single unrepaired DSB is lethal for a cell or may lead to disastrous consequences upon loosing the affected chromosome. Misrepair of DSBs may lead to chromosomal aberrations and other types of mutations. DNA repair is a major mechanism to provide genomic stability.
Genomic instability is a hallmark for all forms of cancer.
Thus, DNA repair is not only a prerequisite for the evolution of cellular life, but it is also essential for ontogenic development. Complex chemical mixtures with unknown genotoxic potential and known genotoxic agents are constantly released into the environment, accidentally or on purpose. Monitoring the food chain and water supply for genotoxic agents and testing the genotoxic potential of novel compounds used in medical and non-medical applications is a major challenge. Mechanism of homologus recombination in eukaryotes Several pathways ensure the repair of DSBs in eukaryotic cells. These DSB repair pathways are conserved in all eukaryotes.