chromosomal DNA extraction E. coli - (Aug/25/2008 )

Hello,

What is the best way to isolate genomic DNA from E. coli?
Does anyone have a protocol for this?

Many Thx

It depends on what next task you will do. just Goooogle and you can find lots of things

I want to use it for Southern so it needs to be high quality
Indeed I find a lot of protocols, all slightly different.
My goal would be to have as less fragmented genomic DNA as possible and when the presence of plasmid DNA can be avoided that would be nice too.

The easiest way to avoid plasmid DNA is to use a strain with no plasmids.

A typical prep would follow the Qiagen miniprep instructions with spinning down and
resuspending in P1 followed by addition of P2. Then, rather than neutralizing with N3, add an equal vollume of Phenol/Chlorofom/Isoamyl alcohol 25;24:1, vortex, spin down and keep the upper layer. Repeat, then repeat with chloroform only. Keep the upper layer and then ethanol precipitate, wash 2x with 70% ethanol, and resuspend in TE.