DNA stability in STE with proteinase K - (Jun/18/2014 )

I'm currently working on genotyping mouse tail snips, however I won't be able to do the phenol-chloroform extractions for several days. If I performed the digest of the tail snips in STE (50 mM Tris, 100 mM NaCl, 1mM EDTA, 1%SDS) with proteinase K, would the samples be stable for up to a week if I stored them at -20°C once I finished the digest? Or should I just wait and do the digest the day before I can do the phenol-chloroform extractions so that I avoid potential degradation of the DNA?

Yes, it's pretty stable in STE at -20. Sometimes we had them there for months, maybe even years (but I'm not sure about quality of that). However, tail DNA is always not exactly a good quality, full of PCR inhibitors. If you need it for PCR, dilute to low concentrations like 10-20 ng/ul and use more PCR cycles.

Lysates stored frozen are generaly more stable than original material, that's particulary important for RNA isolation.