Rescue my DNA extraction - (Oct/15/2009 )

Hi,

I was trying to carry out DNA extraction, but I screwed up while EtOH ppting. I added 70% EtOH (for rinsing), and vortexed by mistake!! So my DNA went back into solution. I centrifuged it again (max rpm, 15mins) and pellet was much smaller (I guess because pption is not efficient from 70% EtOH, and I didn't have any salt). Is there any way to fix this??

I was considering adding 100% EtOH till conc was 95% at least, then adding Na-acetate and incubate @ -20C before spinning. But then the total vol becomes large - 5mL and DNA conc will be very low, but maybe if I add glycogen I can still recover some DNA? Also how to I calc how much salt to add. Normally I add 1/10th of vol of DNA solution, but now my solution is in 70% EtOH not buffer...

Please help!! My sample is very precious since its from a tumor.

Thanks!

u are supposed to etoh wash + vortex. so that the pellet is resuspended and the contaminant is all washed off. then the centrifuge step to get the pellet back again.