A few coffees ago with Lara and Shane, we were discussing the age-old design versus evolution "problem". In my daily reading, I've just stumbled upon this article.

In the article they are just noting that stress is accellerating the reduction of the "protective" tails of the DNA strands (telomeres). Telomeres appear to act (speculation) something like a checksum, the longer they are, the more likely it is that incorrectly duplicated strands will fail to coalesce. When the checksum gets below a certain length (has too few bits to catch the errors), the chances that a DNA strand is going to mis-replicate become extremely high, so cell duplication cannot continue (too many errors) and growth stops (or, if I'm right, cancer and/or mutation become more likely to occur).

Even if the effect is more subtle, the fact that stress is affecting the DNA replication process suggests that the idea of stress accellerating mutation is within the realm of possibility, and would help to explain how evolution comes in fits and spurts... or so I tell myself :) .