[frgoff]

there is redundancy in the system," says Kelly Frazer of Perlegen Sciences in California.

If this is true, then we have another problem on our hands, specifically, the time it takes for evolution to occur. If there are redundant systems in DNA, then mutations will be that much, much less likely to manifest. The mutation would also have to compromise the redundant system in some way, or the mutation would simply be negated by the redundant system and repaired the next generation.

[AndrewC]

If there are redundant systems in DNA, then mutations will be that much, much less likely to manifest. The mutation would also have to compromise the redundant system in some way, or the mutation would simply be negated by the redundant system and repaired the next generation.

You got it! Moreover, the regions contained by both mice and men are "pristine", not one mutation.