storing a sample or its DNA extraction - which is prefered??? (Oct/08/2007 )

hello ALL
what do you think??
which is prefered for further use,study..let's say for forensic studies storing the sample as it is or the DNA extraction??
and why???

I would suggest the DNA would be a better format for long-term storage. Think about it this way: if you only have the tissue, and the freezer breaks down, you will almost definitely lose the DNA, as nucleases become active. If, on the other hand, you purify the gDNA, and freeze it in, say TE, the DNA should remain intact even if such a disaster occurs.

In terms of forensic studies and metagenomic studies I would prefer to keep the samples (store in liquid nitrogen). While such samples are more labile, they do contain more information then a DNA extraction. Rare sequences, damaged sequences, sequences that are hard to amplify or extract for one reason or another, infomation that maybe impossible to extract with todays technology, but may become accessible with improved technology decades from now.

However in terms of cloning work and making plasmids, everyday lab work, I would prefer to keep the plasmid DNA. DNA is more stable, won't die on you, and can be stores at -20 Celsius without trouble.

thanks alot swanny and perneseblue
do u have any papers discussing such issue??

Is you can, save DNA and save some of original sample too.

Water or TE buffer will do. Can store up to say years if using -20C?

thanx alot for passing

i've read that 20% ethylene glycol-propylene glycol preserves cells and tissues integrity, as judged by microscopic analysis, and improves DNA yield and quality.when samples are stored at -4C or -20C.

it seems that it depends on ur aim as perneseblue said..

is there any other ways u can preserve/store ur sample in rather than the sample itself or the DNA extraction ???