This preview shows page 1. Sign up to view the full content.
Unformatted text preview: iagram. har06584_refA_001-020 6 11/4/06 10:09 AM Page 6 Reference A Saccharomyces cerevisiae: Genetic Portrait of a Yeast saturation mutagenesis and to isolate rare mutants. Unlike
E.coli, yeast can grow as either haploid or diploid cells, and
both ploidy levels have useful applications in genetic analysis. A mutant hunt in yeast usually begins with mutagenesis
of a diploid cell. For example, in a hunt for mutations in the
uracil biosynthesis pathway, diploid yeast are mutagenized
under conditions that are expected to yield single mutations.
Meiosis (sporulation) is induced and the 4 meiotic products
(spores) tested for Ura phenotype. If there is a recessive
Ura mutation in the starting diploid cell, there would be
2 Ura , 2 Ura haploid spores (Fig. A.7a). A 2 : 2 pattern of phenotypes in the haploid meiotic products indicates
there is a mutation in a single gene in the original diploid. If
the Ura phenotype is seen in a diploid cell before meiosis,
that cell contains a dominant mutation....
View Full Document
This note was uploaded on 10/03/2013 for the course BI 206 taught by Professor Celenza during the Spring '08 term at BU.
- Spring '08