southern size standards

Ed Siefker via (by ebs15242 from
Wed Jun 25 14:38:11 EST 2008

I'm looking for a DNA size standard I can use with southern blots.  I don't
want to deal with radioactive gel apparatus, so I don't want to end label
my ladder before I run the gel.  The ideal solution would be something dyed
so I could see with the naked eye on the membrane, and mark the sizes with
radioactive ink.  Is there something like this available?

Here's an idea, I can see the DNA ladder in my gel under UV.  Could I inject
a small amount of P32 into each size standard, and then transfer so the size
standards would be visible on the membrane?

I've seen protocols for making size standards from lambda DNA, but these
require probing with lambda DNA.  If I do this, would I include the lambda
probe in the hybridization with my probe?  Do I need to reprobe with the
lambda probe?

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