primer design

Tom Chappell t.chappell at
Wed Apr 1 18:54:16 EST 1998

In article <6fr3co$3c0$1 at>, gen154 at
(p.molloy) wrote:

>Could a PCR work if one of the primers has a 25 base pair homology to the
>template but a 40 mer random base tail extension at its terminus.
>University of Aberdeen

minor point, but a 40mer random tail is overkill  if what you are looking
for is randomness. Calculate how many grams of  oligo you need to have all
the possible random 40mers in the tube... 4 to the 40th is 2 to the 80th
is about 10 to the 24th...

I do random tail PCR's regularly. We use 18 bases of homology with a 20mer
random tail.

Tom Chappell
MRC Laboratory for Molecular Cell Biology
University College London

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