I have a bunch of petite mutants and need to distinguish those that
are mitochondrial petites from those in which the mutation is nuclear.
The problem is, they're diploid (it's a long story), and being petites
they cannot sporulate by any means that I've been able to find. I just
tried the method reported in a recent Yeast volume of sporulating in 10
mM KH2CO3 at high pH, which reportedly abolishes the dependence of
sporulation on respiration, but the damn things still didn't sporulate.
Short of getting them to sporulate somehow, the only thing I've thought
of is to make them aa or alpha-alpha diploids using a GAL-HO plasmid,
then mate them with a complementary diploid, then sporulate *that*. I
have a couple of dozen genotypes to look at, and they lack most of the
standard auxotrophies so it would be kind of time-consuming to go
through that whole procedure for all of them. Does anyone know of an
easier and more clever way to tell whether a diploid petite has a
nuclear or mitochondrial mutation?
zeylcw at wfu.edu
Wake Forest University