Stability of genomic DNA in 1x PBS - (May/18/2010 )
I perform heat-induced genomic DNA extraction from bacterial cells, and at the end they are stored in 4C in 1x PBS. I would like to know if there is any data/paper showing the duration in which they are stable for.
This article from QIAGEN shows that using their Buffer AE purified DNA is stable for up to 8 years in 2-8C. However, of course, the chemical makeup of AE is different from PBS.
Two major things affect DNA stability, pH and lack of magnesium. TE is designed with pH 7.5 to 8.0, and with 1 mM EDTA, to remove residual Mg++ ions. DNA is stable in TE almost indefinitely at 4C (actually, at room temperature also). I would assume that the E in AE is also EDTA. I don't know the other component, but it is likely a buffer for pH control also.
See Qiagen's FAQ no. 730 here:
730 What is the composition of buffer AE?
The composition of Buffer AE is:
10 mM Tris-Cl
0.5 mM EDTA; pH 9.0.
Buffer AE is the elution buffer used in DNeasy Kits for genomic DNA isolation from animal and plant samples, and QIAamp Kits for DNA isolation from clinical samples.