No, while isolation your plasmid you normally will lose your genomic DNA, after the neutralization step and the following centrifugation. The genomic DNA will be in the pellet. Of course you can go ahead and work with this, but I would recommend to work with a suitable genomic DNA isolation kit, available from several suppliers.

I usually use mini-prep isolation for plasmids, where DNA is precipitated in an alkaline medium together with RNA, proteins and other impurities. I think it will be difficult to purify DNA from this pellet, at least you should made it soluble again and then purify as in common DNA isolation protocols. Maybe it is possible, but best way is to follow proven protocols of DNA isolation to have good quality DNA at the end. All the subsequent reactions will depend on the quality of the DNA you will get.

No, thats not possible. You make the gDNA insoluble in the neutralization (denaturation) step. This is also the reason why you have to mix very gentle, otherwise you break up the gDNA and get it into your final plasmid prep as an impurity.

You have to use genomic DNA extraction kit for gDNA extraction. Plasmid DNA is supercoiled as compared with gDNA so this principle is exploited in plasmid extraction kit

Dear all thanks for your answers.

Actually my source for gDNA isolation is plant not from bacteria. Presently we don't have gDNA isolation kit.We Ordered but it takes time.

So can we use the plasmid isolation kit for plant gDNA isolation?

No, you can't for the same reason as mentioned above. gDNA is too big and gets into the pellet during the denaturation step. It doesn't matter if this is bacterial or plant genomic DNA.

No. you will loose all DNA with plasmid extraction kit!

there are many simple protocols for plant DNA isolation without kits, it is match cheaper and more effective. CTAB- based methods are especially good for plants. Of curse, if you have any chemicals available in your lab :)

Thanks Angelika Voronova, I am using CTAB- based methods but the quality of DNA is not that much good. My down stream application is Southern blot.

Yes, you can use a plasmid midi kit for genomic DNA isolation or other similar. Elute DNA with heating.

@Ruslan: Plasmid kits denaturate the genomic DNA. The yield would be very small to not existant due to this.

there are many ways to enhance quality of DNA using standard CTAB-based protocol. I am sure, you have used something (but I do not know what). Addition of PVP to the lysis buffer (polyvinylpirrolidone, soluble form) helps to get rid from many impurities and greatly increases the quality of subsequent reactions. See for the details: Porebski S, Bailey GL, Baum BR (1997) Modification of a CTAB DNA extraction protocol for plants containing high polysaharide and polyphenol componenets. Plant Mol Biol Rep 15(1): 8-15

From the plasmid midi kit you can use only columns and wash and elution buffers. All DNA/RNA extraction kits used the same type of glass fibber or silica membrane. DNA binds to membrane by chaotropic agent, like guanidine salt, NaClO4.

http://www.google.com/patents/EP0649853B1

Also CTAB buffer with 50% propanol can be used for DNA binding on glass fiber.

"Glass microfiber column and method for the preparation and purification of plasmid dna using the same" WO 1999051734 A1

http://www.google.com/patents/WO1999051734A1

"Compositions and methods of selective nucleic acid isolation"

US 7537898 B2:

http://www.google.com/patents/US7537898

http://www.google.com/patents/US8507198

@Ruslan: Ahh, you are using different buffers. This is something you have to say... Thanks for the links.

http://www.google.com/patents/EP1581646A3

http://www.google.com/patents/WO2001014590A2

http://www.google.com/patents/WO2008150838A1

There is a method to purify gDNA from cells that disrupts cells with heat (95ºC) and osmotic lysis. When you finish it after centrifugation you have a solution with gDNA. The questions is, is possible use only the column and the washing buffer to purify the gDNA?