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DNA and RNA Extraction - Help (Aug/10/2005 )


I am trying to figure out the best way to carry out a DNA and RNA extraction at the same time from a sample of blood, cardiac muscle and a pancreas. I have very limited samples of patients, so does anyone know of a way to get both mRNA and DNA out of the same sample?

I have heard Phenol/Chloroform Extractions may work, as might TriZol? Anyone tried either before?



Trizol will work fine.


DNA sequencing reagents

-Daniel Tillett-

thanks daniel. i will try it!

while we are on the topic - has anyone used trizol before? i found some in our lab thats about 6 months old - but its been in a 4deg fridge... would it still work? or should i just not bother trying and buy a new lot?

Thanks again! wink.gif


I don't know how long trizol lasts but if your samples are precious do you want to risk it smile.gif


Better DNA sequencing results

-Daniel Tillett-

Trizol shouldn't go off in 6 months

Trizol will give you RNA with only minimal DNA present. The DNA separates into the acidic phenol phase

-John Buckels-

Tri-reagent is ace, I used it to extract my RNA. If you need ultra-pure RNA afterwards, it might be worth while doing a LiCl precipitation as an additional step. Just resuspend your RNA in water, and add an equal volume of 4M LiCl, precipitate O/N at 4 C. Spin, pellet and resuspend.


There is a protocol for isolating the DNA from the Trizol organic phase. Check the invitrogen website

-John Buckels-

Trizol is the best choice in your case!
I have used that also to isolate RNA and Protein at the same time from precious Patient samples. It works great!And if it has been always in 4 degree, It will go off at least after 1 year.


hi everyone,

i tried trizol and it worked! i am glad!

but i am going to be safe and get new trizol before i start extracting from my patient samples

thanks for all the help smile.gif rolleyes.gif


It might be a good idea to do a test run on a less critical sample just to make sure that the new trizol batch is OK. This is almost certainly not necessary, but it is be better to be safe than sorry. Also don't throw anything away until you know the extraction worked.


Sanger DNA sequencing reagents

-Daniel Tillett-