shanwill
Feb5-12, 02:52 PM
1. The problem statement, all variables and given/known data
You decide to revert an iob- mutant to wild type (IOB+) using different mutagens and find the following reversion rates for each mutagen tested:
2-amino purine - 98%
5-bromouracil - 95%
Nitrous acid - 94%
Proflavin - 2%
Spontaneous - 4%
1. What is the most likely molecular basis of the original iob- mutation?
2. What does the reversion test data suggest about the most prominent mechanism of spontaneous mutations in this organism?
3. You decide to isolate deletion mutations in the IOB gene. Suggest a genetic screen that would enrich for deletion mutations in this gene over other types of loss-of-function mutations.
4. Suggest two genetic tests that would show you have indeed identified iob deletion mutants.
2. Relevant equations
3. The attempt at a solution
1. I assumed that since bromouracil, nitrous acid, and aminopurine all cause transition mutations, the original mutation is likely a transition - but i wasn't sure if that's what they meant by molecular basis?
2. Since I'm assuming the original mutation was a transition, and the rate of spontaneous revertants is very low, I was thinking I'd suggest that the most prominent mechanism of mutations in this organism is not transition mutations - but again i wasn't sure if i was answering what the question was asking
3. I'm at a loss here - any ideas?! *** I was thinking possibly using a mutagen that is known to cause deletions (but I couldn't seem to find any) or one that causes both deletions and insertions and then screening for insertions by the methods described in 4, but I couldn't seem to find a mutagen like that either. HEEEELP!
4. If I could answer number 3, then i was thinking i could use PCR analysis or comparative genomic hybridization, does that make sense?
Your opinions would be much appreciated!
You decide to revert an iob- mutant to wild type (IOB+) using different mutagens and find the following reversion rates for each mutagen tested:
2-amino purine - 98%
5-bromouracil - 95%
Nitrous acid - 94%
Proflavin - 2%
Spontaneous - 4%
1. What is the most likely molecular basis of the original iob- mutation?
2. What does the reversion test data suggest about the most prominent mechanism of spontaneous mutations in this organism?
3. You decide to isolate deletion mutations in the IOB gene. Suggest a genetic screen that would enrich for deletion mutations in this gene over other types of loss-of-function mutations.
4. Suggest two genetic tests that would show you have indeed identified iob deletion mutants.
2. Relevant equations
3. The attempt at a solution
1. I assumed that since bromouracil, nitrous acid, and aminopurine all cause transition mutations, the original mutation is likely a transition - but i wasn't sure if that's what they meant by molecular basis?
2. Since I'm assuming the original mutation was a transition, and the rate of spontaneous revertants is very low, I was thinking I'd suggest that the most prominent mechanism of mutations in this organism is not transition mutations - but again i wasn't sure if i was answering what the question was asking
3. I'm at a loss here - any ideas?! *** I was thinking possibly using a mutagen that is known to cause deletions (but I couldn't seem to find any) or one that causes both deletions and insertions and then screening for insertions by the methods described in 4, but I couldn't seem to find a mutagen like that either. HEEEELP!
4. If I could answer number 3, then i was thinking i could use PCR analysis or comparative genomic hybridization, does that make sense?
Your opinions would be much appreciated!