Counting a character in MS-Excel (Mac)

Mark Yeager yeagerm at jeflin.tju.edu
Tue Aug 29 09:46:05 EST 1995


In article <Andy.Law-2908951227440001 at pc0519.ri.bbsrc.ac.uk>,
Andy.Law at bbsrc.ac.uk (Andy Law (Big Nose)) wrote:

> This is not the most efficient way of solving this problem (In my
> [probably not very humble] opinion). The problem is that Excel is pretty
> slow at doing these macro thingies, and if you wanted to calculate the Tm
> based on four defined bases you would have to step right through the oligo
> sequence four times.

I understood the original poster wanted to calculate the number of bases
in order to get the extinction coefficient to then calculate the
concentration of the primer from the A260.

Speed is no problem for me - the cells are calculated before I finish
blinking. If I needed to count through thousands of bases then of course
there are more efficient schemes. But these are only 20 mers.

For Tm I actually use the values calulated by the Whitehead Inst. program
PRIMER, but on the spreadsheet the best correlation with those values
comes from the empirical relation:

   Tm= 0.41(%GC)+69.3-650/L    (L = length of primer in bases).

-- 
--  -.--
Mark Yeager ->   yeagerm at jeflin.tju.edu
Dept. Pathology and Cell Biology, Thomas Jefferson Univ., Phila., PA




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