Storage of gDNA? - (Aug/25/2005 )

Having some debate with some colleagues about long term and short term storage of genomic DNA.

Perhaps one of the most common comment I have heard in favor of storing DNA at 4C for long term is that freezing at -20 or -80 will cause shearing/nicking of genomic DNA. But is the amount of shearing bad enough to justify the faster rate of degradation at 4C versus -20 or -80? Any thoughts?

Depending on your application, probably not.

I would store genomic DNA a 4C for a week with no worries.

A lot of it would depend on how many freeze/thaw cycles I would be taking thru.

If, for example I knew it would be used several times over the course of a month, then pop it in the fridge.

If you are going to use it sporadically to rare occassions then -20 is good. Long term storage (years between use) then put it in the -80.