Nonradioactive vs. radiolabelled probes

M K Bennett pamkb at
Thu Mar 3 04:16:25 EST 1994

Marion Freistadt (mfreis at wrote:
: Has anyone compared the sensitivity of non vs. radiolabelled probes in
: southern blots, all else being equal?  We are having difficulty detecting a
: single copy sequence used the Genius kit; but we know the gene is there by
: PCR.  The positive control in the southern (plasmid DNA) works, although we
: have not yet titrated the sensitivity, hoping it wouldn't be necessary.  I
: was thinking maybe I should go back to 32P.  Comments?

My limited experiance with non-radio probes says that they are always
less sensative than 32P.  I have never got them to work effectivly when
probing northerns, Southerns or plaque lifts (lots of targets).  In the
end the fact that generally you get your data with 32P leads me to always
use it.  It would be nice however not to have to use it.

Mike Bennett (D.Phil)

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