PCR mistakes
Koen De Smet
k.desmet at nospam.ic.ac.uk
Thu Jun 4 01:54:44 EST 1998
Richard P. Grant wrote:
>
> In the first instance, simply Taq, yes.
>
> I've used the same idea for Pfu too. Taq I've tended to do 25 cycles, Pfu
> 30 cycles. Taq was a home-made buffer, Pfu (cloned) was the supplied, but
> I've always titrated Mg2+ concentration.
>
> It's a bit worrying that you're getting errors using a proof-reading
> enzyme. I would suggest trying different enzymes.
I have used Deep Vent (NEB) to amplify and clone several ORFs from Mycobacterium
tuberculosis, and found no seqeuncing errors up to now.
>
> Silly question - how do you know you have the mistakes? Are you comparing
> with a published sequence?
>
Maybe not so silly. In one of my clones, I had some differences from the sequence in
the EMBL/GenBank database. But when the genome of M. tb strain H37Rv was sequenced
(finished last December BTW), this ORF was identical to the sequence I had from my
amplified product, but different from the original one in the database.
Koen De Smet
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