DNA in buffer
Jose de las Heras
(by josenet from tiscali.co.uk)
Sun Mar 4 22:06:32 EST 2007
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> "Jose de las Heras" <josenet from tiscali.co.uk> wrote in message
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>>> How long can you store plasmid DNA (~6kb) in TE buffer at -20C without
>>> no mutations?
>> You may get some degradation, perhaps, if there's some contaminant
>> nuclease... but I don't think you'll get mutations.
>> It's better to store plasmids frozen in TE than as a bacterial stock in
>> glycerol, where you *may* get mutations.
> would you like to explain why this is so?
Plasmids, in TE, can't mutate. If there are nucleases in the buffer they may
degrade... but if your TE is clean, you'll have plasmid for a long long
Bacterial stocks, although quite stable, are alive. If a mutation is going
to happen anywhere, it'll be when the plasmid is in the bugs. To amplify the
plasmid you'll streak from the stock and pick a single colony... As
transformation is so simple, and it doesn't take longer, I don't see much
use for having bacterial stocks at -70. Plasmids are just easier to keep.
I haven't had any problem that i could blame a mutation in the stock for,
although I heard of others (yet, you never know how sure "others" are, too
many myths and unfounded stories circulating around), but I don't see any
advantage in keeping a stock like that. Plasmids alone can't mutate, are
easier to store and handle, and transforming bugs when you need them doesn't
take longr than growing from glycerol stocks... so I don't use them.
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