In article <DHE0L4.L3M at riker.neoucom.edu>, xzhang at riker.neoucom.edu
(Xiaolan Zhang) wrote:
>I am performing a genomic southern using 6 REs and DNA from 2 species. My
>probe is a 70bp fragment from the 5' end of my cDNA which I have labeled
>by random priming. The probe does not appear to contain repeat sequences.
>The DNA was digested well and transferred to nylon membranes.
>Hybridization at high stringency and exposure of X-ray film for 1 week was
>used. The blots are very clean.
>>My results have been consistently puzzling. There are 8 bands ranging in
>size from 1 to 8 kb that appear in all lanes regardless of RE or specie.
>These bands vary in intensity but are about the same as the specific
>pattern over which they are superimposed.
>>I think that if there was a contaminating DNA in the samples it would not
>yield the same bands after digestion with different REs. I tested my
>loading buffer for contamination by running just buffer and found none.
>There should not be so many introns covered by such a short probe. And
>they could not all happen to have the same RE sites.
>>What could these bands be from and how can I solve this puzzle?
Mnnnn, I cannot think of a good answer.
However, it seems that a there may be a problem in the electrophoresis step.
How about dye solution for electrophoresis? Isn't it contaminated?
Ah, this could not be any help. Sorry.
Laboratory of Genetics
Faculty of Science
Toyonaka, Osaka 560
shiraga4 at bio.sci.osaka-u.ac.jp