Your formulas are basically the same. What Adela was using it to
determine was annealing temperature, which, for short oligos, is
generally taken as 5-6 degrees below the Tm.
On 22 Nov 1995, Thomas Urbig
> Date: 22 Nov 1995 16:44:03 GMT
> From: Thomas Urbig <Thomas at hastingsmac2.fas.harvard.edu>
> To: methods-and-reagents at net.bio.net, Adela.Torres at uv.es> Subject: Re: Annealing temperature for oligos
>>Adela.Torres at uv.es (Adela Torres Calatayud) wrote:
> >Hi everybody:
> >I'm currently working on DNA non-radioactive cycle sequencing, and I'd like to
> >know if there is a reliable formula by which I can choose the annealing
> >temperature of the PCR program when I'm sequencing using custom-made oligos.
> >Right now the formula I'm using is:
> > 2(A+T) + 4(G+C) - 6 = T ann.
> >But it didn't give me good results when I tried it. So if there's anyone out
> >there that can help me, thanks very much! E-mail or post.
> > Adela Torres
> > (Adela.Torres at uv.es)
>> I don't where you got the formula, the one I am using Is
>> Tm = 4(G+C) + 2(A+T)
>> Ref.: Thein and Wallace 1986, Human Genetic Deseases: A practical approach, K. E. Davis, ed., IRL Press
>> Hope that helps