4 replies to this topic

[beta]

Hi,
During DNA precipitation i always incubate it in isopropanol overnight at 4^oC, and instead of getting a nice pallet of DNA my DNA either be in goo form or jelly form. Is there any different between precipitate DNA for a couple hour in room temp and doing it overnight at 4^oC. If there is whats is the reason.

[bob1]

IPA pellets are often gel like.  It doesn't really matter which temperature you ppt at, the amount of extra DNA (or RNA) you manage to precipitate is minimal.

[beta]

thanks bob1 =)
What about the time period then, will it effect the yield of DNA.

[bob1]

In theory yes, in practice, not really - you might be able to squeeze a few extra micrograms out, but it also increases the risk of precipitating any extra proteins or RNA that are still there.

[beta]

What happen to my DNA is that, after kept in -20 it tend to be gel-like and i can actually spins down the gel and collect the solution above it. When i measure the OD of the solution i can still get a good yield of DNA. AS for the gel i'm not sure whether it is DNA, protein or salt.

oh, and the purity is way below 1.8 (A260/280)