“DNA Double-Strand Break Repair: All’s Well that Ends Well,” Claire Wyman and Roland Kanaar, Annual Revue of Genetics, vol. 40, 2006, pp. 363–83 (http://dx.doi.org
40.110405.090451). (Thanks to S.K. Moses for bringing this to our attention.) The authors explain that:
Breaks in both DNA strands are a particularly dangerous threat to genome stability. At a DNA double-strand break (DSB), potentially lost sequence information cannot be recovered from the same DNA molecule. However, simple repair by joining two broken ends, though inherently error prone, is preferable to leaving ends broken and capable of causing genome rearrangements.
(That’s an excerpt from the article “Icky Cutesy Research Review —Research reports that are icky and/or cutesy”, in AIR 13:4.)