I've got beans going on 5 years and they popped, not 100% success but at least 80%.
Its all about keeping the moisture levels at a stable level. by keeping them in containers with a moisture absorbant, you will eliminate the "start to germ" process. And by keeping them in the fridge you put them in a stasis mode.
Freezer is just the same. just better packaging with rice is needed.
If its in a drawer or back of the cupboard just somma, then yea expect no more than 2 years.
And I dont think any damage to the DNA would occur, but I dont fully know...
Awe