DNA isolation - ethanol precipitation related (Jan/10/2011 )

Does the concentration of alcohol added affect the amount of DNA that precipitates out?

pavi on Tue Jan 11 02:46:03 2011 said:

It depends on what concentration is your alcohol at? Say, if you added 60% or 80% alcohol instead of 70% alcohol, it would not make a huge difference, but if you added like 20% alcohol, then the DNA that would precipitate out would be very little because it would dissolve in the water.

The most important thing for ethanol precipitation is to end up with a final ethanol concentration of 70%. This is usually achieved by adding 2.5 volumes of 100% ethanol to the DNA solution you want to precipitate.