gruther at bilbo.bio.purdue.edu
Wed Sep 8 12:00:37 EST 1999
In article <7r2pes$87i$1 at nnrp1.deja.com>, felicity_austen at my-deja.com wrote:
> Limitation of starting material rules out RNA binding kits currently
> available to me for extraction (eg Qiagen) as retained RNA will probably
> equal my entire sample. I use acid guanidium phenol chloroform method
> similar to Chomczynski (1986?). A lot of genomic DNA is in my samples.
> Intended use of RNA is cDNA subtraction which means I cannot have
> genomic DNA (as little as technically possible).
If you're doing the acid phenol/guanidinium extraction properly, that is,
if the pH is right, genomic DNA should partition into the organic phase
and shouldn't be an issue. I've done a gazzillion preps from flies and
rats and never seen any genomic DNA visible on an agarose gel stained with
EtBr (which isn't to say that there isn't *any*, but it's good enough for
RT-PCR). I'd check the pH of the phenol. Best of luck.
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