Is DH5alpha derived from K12?

Arnoud van Vliet arnoud at
Mon Apr 6 20:03:03 EST 1998

Hi Doug,

DH5 alpha is derived from K12. Succes with your PCR depends on what
gene you are trying to amplify. DH5 alpha has gone through a long
series of mutations etc to make it useful for special cloning
purposes. The Biolabs catalogue I have here gives as genotype:

F' (or F-) endA1 hsdR17 supE44 thi-1 recA1 gyrA (Nal-r) relA1
delta(lacIZYA-argF)U169 deoR (phi80dlac[delta]lacZM15

Just look in handbooks or catalogues for what these codes mean. If you
want one of the K12 least manipulated, my advise is to go for MC4100.
Hasn't been changed that much

hope this helps

On Mon, 6 Apr 1998 15:32:00 -0400, Doug Stemke <dstemke at>

>I'm trying to PCR out a gene that I saw through a GCG search.  However the
>original strain was K12 and what we have around the lab is DH5alpha, and I
>have lots of chromosomal DNA from this strain.  I rather not waste
>polymerase so was wondering if DH5alpha was derived from K12.
>Cheers and thanks.
>Douglas J. Stemke, Ph.D.
>Biological Process Technology Institute
>University of Minnesota
>St. Paul, MN
>dstemke at

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