problem with 5-FOA plates

Andrei Popov ANDREI.POPOV at
Tue Sep 19 06:29:10 EST 1995

>My problem is that seven of eight yeast colonies that grow on this
>medium will still grow on minimal medium plates without uracil. Please
>post here or to my email address: kjshaw at Thank you for your time.

 Sounds like you have uracil contamination in your URA- plates.
Most often comes with agar.
Another tip: try to re-streake colonies from primary 5-FOA plates
on another 5-FOA plate and then analyse for the plasmid loss.
Primary colonies usually contain a mixture of cells with and w/o
ura3-plasmid. I observed this with centromeric plasmid cant say anything
about 2-mu.

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