Tm. calculation

Jim Litts littsj at zgi.com
Wed Jan 22 21:45:05 EST 1997


The first eqn. is a good estimate for primers, but not as good as nearest
neighbor based estimations.  The second is for large fragments of average
base composition and is inappropriate for oligos as a rule.

In article <Pine.SOL.3.91.970121133519.3846E-100000 at cmu>,
ratana at CMU.CHIANGMAI.AC.TH (Ratana Banjerdpongchai) wrote:

> > > 
> > >     I have the problem about primers's Tm. calculation. Between 2 
> > > equatios we have, one is "Tm.=4(G+C)+2(A+T)" and the other one is Tm.= 
> > > 85.1+0.41(log[Na])-(675/n).  my primers are not shown the same or even 
> > > neary value , for example, 80.0C for the equation 1. and 61.0 for the 
> > > equation 2. 
> > >     Can anyone suggest me about these.?  the different annealing 
> > > temperatures i have give me the different results . it's seem to be that 
> > > the annealing temperature calculated from equatiuon 1. is better.
> > >     thank you very much
> > > 
> > > Pongsathorn  Dhumtanom
> > > biochemistry  Medicine
> > > chiangmai U. 
> > > Thailand
> > > 
> >

-- 
Jim Litts
Zymogenetic, Inc.
Seattle, WA USA
My comments are my own and not my employer's.



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