DNA sequencing

Michael L. Sullivan mlsulliv at facstaff.wisc.edu
Mon Aug 12 10:57:04 EST 2002

I seem to recall that some strains that are not mutated in endA (and 
maybe some other locus) make poor template DNA.  Many commercial kits 
for DNA preps (like those from Promega and Qiagen) include guanidine 
wash steps to alleviate this with endA positive strains.  I think 
both the strains you mention are endA positive.

Hope this helps.


>Dear All,
>         we have a really great DNA seqencing service here and I usually
>send them plasmid DNA extracted from E. coli XL1 with perfect results.
>However, I have recently tried sending them DNA from BL21 RIL and GM2163
>with bad or no results.
>The site http://circuit.neb.com/neb/faqs/dam_dcm/faq_dam_dcm.html shows
>GM2163 has a "bad name" for DNA quality.  Is poor sequencing one of
>it's crimes?
>Regards, Mike.


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