LiCl in DNA prep

[rcowherd at mail.med.upenn.edu]

Rodney Earl Pettway wrote:

> Can anyone answer this.  What role does LiCl play in DNA extraction
> protocols?  This person in our lab uses it in their DNA extraction
> protocol and I can not figure out why and they don't know either.

> Rodney Earl Pettway


In Berger and Kimmel's METHODS IN ENZYMOLOGY (Volume 152):   Guide
to Molecular Cloning, chapter 5 by Donald M. Wallace says that 
"Since LiCl is highly soluble in solutions at -70[degrees], salt is
not coprecipitated with the nucleic acid."

I use this salt instead of sodium acetate and I never feel that I
have to do a 70% ETOH wash to remove excess salt.  I only do a wash
if I've precipitated with 2-propanol (just to "get rid" of the
isopropanol.)  After having done it this way for 6 years I've never
had a problem with it...

Bob Cowherd
Univ. of Penn.
(215) 662-2071