Genetic radiobiological effects are manifested through which mechanism?

• A. Altered membrane permeability
• B. Direct spread of mutant mitochondria
• C. Replication of mutated nucleic acids
• D. Transmission of viruses

Answer: (C)

Genetic radiobiologic effects come from damage to DNA that is then copied as cells divide. Ionizing radiation can alter nucleic acids in ways that, when the cell replicates its DNA, mutations are carried into the newly formed DNA strands. In other words, the mutated genetic material is propagated through replication, producing heritable genetic changes in daughter cells or future generations if germ cells are affected. The other possibilities describe non-genetic or non-heritable processes, such as changes at the membrane level, transfer of mitochondria, or viral transmission, which aren’t the mechanism by which radiation-induced genetic effects are manifested.