You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
You are using nitrosoguanidine to "revert" mutant nic-2 (nicotinamide-requiring) alleles in Neurospora. You treat cells, plate them on a medium without nicotinamide, and look for prototrophic colonies. You obtain the following results from two mutant alleles.
a. With nic-2 allele 1, you obtain no prototrophs at all.
b. With nic-2 allele 2, you obtain three prototrophic colonies, A, B, and C, and you cross each separately with a wild-type strain of Neurospora. From the cross prototroph A × wild type, you obtain 100 progeny, all of which are prototrophic. From the cross prototroph B × wild type, you obtain 100 progeny, of which 78 are prototrophic and 22 are nicotinamide requiring. From the cross prototroph C × wild type, you obtain 1000 progeny, of which 996 are prototrophic and 4 are nicotinamide requiring.
Explain these results at the molecular level.
Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.
Conclusion
Inducing mutations is a powerful tool that geneticists use for generating phenotypic variants. These variants can then be studied to identify the mutated genes as well as the gene products that the wild-type genes encode. These studies can be extended, in some cases, to unravel biochemical pathways or identify protein interactions. The creation of revertants can be used to identify additional genes (e.g., suppressors) and their gene products.