Colin MacDiarmid (macdiarm at sbsu1.auckland.ac.nz) asks about
making a diploid from two mating strains with identical markers.
In addition to some cute tricks mentioned by others, like Peter
Linders 2-plasmid masking approach, here's what we do with
S. cerevisiae.
We take what I call the Peeping Tom approach! After 3-4 hours
of mating on rich plates, you can streak cells on the edge of a YPD
slab and identify zygotes under the dissection microscope -- mating
shmoos, often with a medial bud; the morphology is pretty easy to spot.
Micromanipulate them out onto the slab and let them grow up.
This has the advantage of being fast, too; no overnight plate growth
before you streak for singles. Check the final colonies for
mating, sporulation, etc. to be sure they really were zygotes.
-- Mitch
--
M. Mitchell Smith mms7r at Virginia.EDU
Department of Microbiology (804) 924-2669
University of Virginia
Charlottesville, VA 22908
