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multiple bands for genomic DNA extraction - (Apr/26/2012 )

I have doing my final project about extracting genomic DNA from bacteria for PCR and RFLP.
I used this protocol for genomic dNA extraction:
1)cell lysis by SDS
2)Frreze and thaw method 3 times by liquid nitrogen
3)phenol chloroform extraction
4)ethanol precipitation
but when the DNA was run on gel, it gave multiple bands instead of one band.
Could you please help me?


There is a possibility that your sample is being degrated by the DNases. Do you have anything such as EDTA present that would prevent degredation?

A few colleagues of mine, along with myself have been trying out newer methods for extraction of gDNA and we've come across a kit that is pretty interesting. It is called PureLyse by this company out of California called Claremont Bio. The protocol is very short and thus far I've had no problems adding my sample into PCR and getting proper amplification. Here's the link if you want to see it.

Let me know if this helped ya out.


Could you post a picture? It is a bit unusual to get bands from genomic DNA, usually just a big blob and maybe a smear.


This company have a useful gadget for cell lysis using liquid nitrogen, you can just mechanically grind it once, rather than thaw and freeze 3 times

-jen coalson-