I just don't know but I have read where DNA was extracted from mummies that were really, really old. I don't know if that info is all that helpful, mummies were somewhat preserved.:slap::nevermind:
Just read an article in Forensic Science journal about DNA degradation in bones. Interesting that weathering increases DNA. Also, the femur is the best bone for extracting DNA. I copied the link, but it didn't work and now I can't find it:banghead: