Detection limits of 32P ?

Daniel Mytelka mytelka at
Fri Apr 16 17:15:21 EST 1993

In article <1993Apr16.100955.2335 at> afc at writes:
>In article <bheymann-150493171011 at>, bheymann at (Bernard Heymann) writes:
>> In article <11857.jdboer at>, jdboer at SOL.UVIC.CA ("Johan de Boer")
>> wrote:
>>> We have some dispute about how much 32P end-labelled DNA fragment can be
>>> detected by autoradiography. I am sure there is someone who has a pretty
>>> good idea. Any takers?
>>> Johan de Boer
>The area that the signal occurs in is important. 1 CPM in a 1 micron spot
>would be easy to detect in an in situ.

My rough estimate is that this would work out to be about 40,000
molecules of DNA, assuming that it was 100% labelled.

Dan Mytelka
Dept of Molecular and Cell Biology, Berkeley
mytelka at

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