southern - loading DNA (Apr/18/2006 )

hi
to run DNA for a transfert, do I need to to add ethiBromid to the gel and do I need to add loading buffer to my DNA sample.
does it onterfer with the southern
thanks

hi
EtBr should be loaded with the sample for visualization. It does not interfers with southern (same as in northern assays).

as far as loading buffer...depends on your detection method.
sometimes with chemi detection, I get a little bit of smearing across the gel where the loading buffer was...so I usually just dilute it 1:10 and add a very small amount (you still need your sample to sink into the well, yeah?)

by the way, the 'smear' I sometimes see from where the blue juice transfers to the membrane, is clearly distinguished from a good tight band...but looks tacky if you might ever want to publish the results