genomic DNA is getting degraded while isolation - (Nov/16/2006 )

hi!
well i am isolating genomic DNA from rice leaves using dellaporta method... but unfortunately when i run the samples on the gel they appear as a continuous smear indicative of degradation!

Please suggest me at probably which step there might be some chances of degradation... its really very urgent!!!

---

Hi there,

Two things are possible:
1) Mechanical sharing of DNA
avoid vigorous shaking and mixing at all stages, treat the solution with DNA very carefully, mix softly, avoid too much vortexing, just mix the tubes by inverting up and down.
2) Enzymatic sharing:
use only reliable kits, reagents and solutions that are definitely free of nucleases!
Regards,
rasap

---

I'm curious about what you expected to see on a gel. Genomic DNA will look like a smear on any standard agarose gel due to fragmentation during preparation. There would typically be a bright band right at the edge of the well, having most of the long DNA fragments. The only way you would see sharp bands would be in a pulse field gel, and even there it is difficult, and requires special care and agarose embedding of the cells during lysis and DNA purification. Likely the DNA is perfectly fine for most applications.

---