Re: Genomic v. Plasmid Extractions

Hello,

Nowadays most labs use commercial kits for plasmid extractions. The selectivity is then in the elution step, where the buffer has the exact salt concentration to elute plasmid DNA and not chomosomal DNA. If you did not use a binding column, but used lysis-deproteination- precipitation, I guess you have precipitated the genomic DNA as well. Many methods are available to extract DNA, Ausubel is only one of them. Maybe try to find a commercial kit, they are usually very fast and convenient.

Hope that helps!

A mad scientist

Moderator's Note: If you use a protocol designed for plasmid DNA, you might not isolate high molecular weight bacterial genomic DNA (although you should get some degraded DNA). You can find protocols for bacterial genomic DNA by a google search or buy a kit from a commercial supplier.