How low can you go (Nuc Acid pellets)?

Jim Owens jow at
Fri Mar 25 08:43:31 EST 1994

In article <1994Mar21.223751.28764 at> Brian Foley,
brianf at writes:
>David Sang-shin Lee (davidlee at wrote:
>: I was wondering....When precipitating DNA or RNA, how little nucleic
>: can you have before the pellet (after centrifugation) becomes so small 
>: it's invisible?
>	It depends on how good your eyesight is, and how clean your DNA 
>is.  Often times the pellet I see is mostly "other stuff" and not DNA. 
>know that when I use real pure DNA for sequencing I cannot see the
>when I have precipitated 5 micrograms of plasmid.  

It also depends on the size and conformation of the DNA.  Long, linear
DNA precipitates are more easily seen than closed, circular, coiled
plasmid DNA which is more easily seen than the same amount of small PCR
fragment which is more easily seen than oligonucletide precipitates.

I do not have any numbers off the top of my head, but that has been my

Good luck,

Jim Owens

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