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Unformatted text preview: cut in a given cell, HOmediated transposition can occur from MAT to one of the
storage loci or in the other direction. This observation
demonstrates that in normal SIR strains, the silencing of
the storage loci ensures that MAT serves as recipient and
the storage loci as donors in the switching process. As a
consequence, in wild-type cells, mating type information
ﬂows in only one direction—from the storage loci to MAT. The Role of HO in Mating Type Determination
and Stability Serves as a Paradigm
Pedigrees of cells undergoing HO-mediated mating type
switching have revealed a few rules governing mitotic cell
lineages during development (Fig. A.12). In a typical pedigree analysis, investigators tease apart the mother and
daughter cells in each cell division by delicate micromanipulation under a microscope so that they can examine
each one individually. The ﬁrst generation arises when a
spore germinates to produce the spore (S) and the ﬁrst
daughter (D1) (Fig. A.12a). In the...
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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