Chapter 5 Study Questions
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- You are working with a prototrophic model organism (e.g., a fungus). You are interested in finding genes involved in synthesis of proline (Pro), an amino acid that is normally synthesizes by this organism.
- How would you design a mutant screen to identify genes required for Pro synthesis?
- Imagine that your screen identified ten mutants (labelled #1 through #10) that grew very poorly unless supplemented with Proline. How could you determine the number of different genes represented by these mutants?
- If each of the ten mutants represents a different gene, what will be the phenotype of the F1 progeny if any pair of the ten mutants are crossed?
- If all ten mutants represent the same gene, what will be the phenotype of the F1 progeny if any pair of the ten mutants are crossed?
- Draw the expected results of a series of complementation tests (crosses), in the form of a table, for five yeast mutant strains where there are at least three different mutant loci, and one of the mutations involves a double hit (two loci are mutant in the same strain).
- Students create a mutant coli strain that is auxotrophic for methionine. Three students build plasmid DNA libraries from wild type DNA from the parental strain. Student A uses EcoRI to clone the restriction fragments. Student B uses HindIII and student C uses XhoI. Each transforms the auxotrophic mutant strain with their library. Student A gets lots of prototrophic colonies on minimal medium, while students B and C don’t get any. Explain what might have happened. The student’s control experiments indicate that the transformation protocol worked.
- Figure 5.4.4 shows how we can rescue an a– strain with a plasmid carrying an a+ Could we also rescue this strain by growing the cells on media containing Enzyme A (the product of the a+ gene)? How about the product of Enzyme A?
- You are working with a prototrophic model organism (e.g., a fungus). You are interested in finding genes involved in synthesis of proline (Pro), an amino acid that is normally synthesizes by this organism.
