What is the most common effect of DNA damage from exposure to ionizing radiation?

What is the most common effect of DNA damage from exposure to ionizing radiation?

• A. Double-strand breaks
• B. Small base-pair lesions
• C. Single-strand breaks
• D. All of the above happen in equal proportion

Answer: (B)

When ionizing radiation hits DNA, it triggers water radiolysis and produces reactive species that attack the bases. This leads to a large number of small chemical changes to the nucleotide bases—oxidized bases, abasic sites, and other base lesions. These base alterations occur far more frequently than breaks in the DNA backbone. Breaks in one strand do occur and double-strand breaks can happen, but they are less common than base damage, and double-strand breaks, while highly harmful, are not the most frequent outcome. So the most common effect is small base-pair lesions, rather than backbone breaks.

When ionizing radiation hits DNA, it triggers water radiolysis and produces reactive species that attack the bases. This leads to a large number of small chemical changes to the nucleotide bases—oxidized bases, abasic sites, and other base lesions. These base alterations occur far more frequently than breaks in the DNA backbone. Breaks in one strand do occur and double-strand breaks can happen, but they are less common than base damage, and double-strand breaks, while highly harmful, are not the most frequent outcome. So the most common effect is small base-pair lesions, rather than backbone breaks.