genomic DNA stroage conditions - (Oct/25/2005 )
Does anyone have any suggestions on the long term storage conditions of genomic DNA? We are making clones from large fragments of the genome and so need full lentgh fragments.
According to most protocols 4C is recommended but I have recently found that the DNA stored under these conditions is degraded quite rapidly. Is there any reason for not freezing it?
for the best long term storage, lyophilize the DNA in aliquots and store at -80
for -20 and for 4, make sure it is properly buffered. also make note that repeated freeze/thaw cycles are hard on molecules
You probably were staoring your DNA in water? Stored of DNA in TE buffer is stable for long periods even at 4 degrees. At -20, it is stable for years.
I store linearized plasmid/PCR product at -20 and plasmids at 4 in nuclease free water or Tris. I do not like EDTA because it hampers sequencing reactions.
DNA stored in water is subject to acid hydrolysis due to the low buffering capacity of the water. In addition, EDTA will prevent the action of any contaminating nucleases, whether in be in the water you use or an impurity in the DNA isolation protocol. Thus, it is a smart move over long periods of time to store your DNA in TE buffer at 4 degrees. If you must store in water, I recommend freezing at -20.