Table 1.

Relationship between the physical characteristics of the incident radiation, the chromatin architecture at the DSB damage site, the utilized repair mechanism (pathway) and the types of potentially generated chromosomal aberrations or epimutations.

Repair Pathway	Chromatin Domain Type (Architecture and Function)
	Euchromatin		Heterochromatin
cNHEJ	short deletions (due to DNA-end "cleaning") interchromosomal translocations and other aberration types	x	x	x
ATM-NHEJ	x	x	short deletions (due to DNA-end "cleaning") interchromosomal translocations and other aberration types (compared to NHEJ, chromatin decondensation increases the risk of aberrations but, at the same time, Hc is more resistant to DSB induction than Ec) epimutations	x
HR/RNA-HR	highly precise	highly precise	x	x
ATM-HR	x	x	epimutations	large deletions complex translocations (due to "premature" aberrant recombination between unmasked repeats in disintegrated domains), interchromosomal aberration types epimutations
Alternative pathways (A-Ej)	large deletions translocations (both due to principal interaction bentween repeats)	large deletions complex translocations (both due to principal interraction bentween repeats and chromatin fragmentation) interchromosomal aberration types	large deletions translocations (both due to principal interraction bentween repeats) epimutations	large deletions complex translocations (both due to principal recombination between repeats and chromatin fragmentation; for a higher repeat content in Hc, more serious damage than in Ec) interchromosomal aberration types epimutations
	Low-LET	High-LET	Low-LET	High-LET
	Radiation quality

Ec: euchromatin, Hc: heterochromatin, Low-LET: ionizing radiation with low linear energy transfer, High-LET: ionizing radiation with high linear energy transfer, X: repair pathway less relevant or irrelevant under the given condition (factor combination). Processes responsible for the generation of particular aberration types are indicated in brackets.