Dear Zhaomin et al.,
Even with ars sequences, we see a "healthy" loss of plasmid in a nonselective
medium. Plasmid pFL20 has both an ars and a stb sequence. I believe the
second element is what really boosts the retention of this plasmid (check out
MCB 6: 80-89). We often want to lose a plasmid to test for plasmid-conferred
phenotypes while screening a library. Two to three days growth on YEA is
plenty for this purpose. Hope this helps. Be sure to check out the
"Pombology: A Fission Expedition" workshop if you are at the meeting in
Madison next month.
I'd rather be fission.
I have a quick question for the fissoners. If a plasmid has an ARS from
S. pombe, what is the chance for the plasmid to be lost after a few
generations of growth in non-selective media? Good? Bad? One in a
million, in a thousand, or in a hundred?