Regarding plasmid and genomic DNA purification

[Natldnel]

Hi... I have a question regarding the difference between the procedure of performing a plasmid DNA purification and a genomic DNA purification.

Basically, at which step and what exactly determines whether the plasmid DNA or the genomic DNA will be obtained? Both have similar processes namely lysing the cell, removing the protein and RNA and such and finally obtaining the desired component, but which part exactly is the difference between obtaining plasmid DNA and genomic DNA?

Thanks... Hope my question is understandable...

[Benjamin]

we can determine whether the plasmid DNA or the genomic DNA by gel running,genomic DNA is generally larger than plasmid DNA,thus through DNA recovery,we finally obtain what we want

[chemistry_freako]

Yup - by carrying out agarose gel electrophoresis, we can compare the band(s) of our plasmid DNA, as well as chromosomal DNA (if any), with the DNA ladder loaded in the first well, thus allowing us to know the size of the fragment, and if we have obtained what we want.