DNA precipitation - (Mar/16/2009 )

HI Dear

Im trying to extract DNA from whole human blood by following the non organic method
(T.E buffer).Following all steps till to protein precipitation,DNA didn't pricipitate by adding isopropanol.I have also used 3M Na Acet.pH 5.5 but no result.I face the problem someone can help me!

use 1/10 vol. of 3M sodium acetate pH 5.2 along with 2.5 vol. of 100% cold ethanol and add about 10 micrograms or so of glycogen. Then keep at -80 c overnight. Spin down the next day in the cold at maximum speed for about 20-30 minutes. That should work. Wash your pelllet with cold 70% ethanol and spin down again. Air dry and resuspend.

Hi, why is there the difference % usage in the ethanol in the 2 different steps (purpose?)
I have heard previously to store either -80 for a couple of hours and -20 overnight. What does the low temperature storing used for used for?

Have been trying to do mice tail genotyping but PCR alway doesnt have bands and thus to do DNA precipitation but there isnt any spiderweb like DNA after adding Soduim acetate and 100% etoh...

Adding 2.5 volumes of pure ethanol to 1 volume of water solution results in a 2.5/3.5 = 5/7 = 70% solution of ethanol. So, the wash is just washing with the same concentration of ethanol. There is near total disagreement about the need or effectiveness of chilling the solution. Some think it has no effect, but I'm in the community that thinks it does. It's easy to put it in the -80 for 30 minutes, and it forms a gel. I then put it directly into the high speed centrifuge.

phage434 on May 5 2009, 04:20 PM said:

*camile* on May 5 2009, 02:02 AM said: