DNA is the carrier of the genetic instructions in all living organisms. Its
integrity is of vital importance for a faithful transmission of the genetic information
and for the proper fimctioning of cellular processes. However, the DNA molecule is
susceptible to alterations caused by both intrinsic chemical instability (e.g.
deatninatioll, depurinatioll etc.) and by a wide variety of environmental and
endogenous compounds. The most prominent DNAwdamaging physical agents arc
ultraviolet (UV) light and ionizing radiation (X-rays and y-rays). DNA damage can
disturb cellular processes and can have severe consequences on human health. Its
direct effect at the cellular level is inhibition of vital processes, most notably
transcription, replication and cell cycle progression. Accumulation of lesions in
DNA can either lead to cell death by apoptosis or to permanent mutation
