After irradiating wild-type Neurospora a geneticist finds two leucine-requiring auxotrophic mutants. He combines them into a heterokaryon, and discovers that it is prototrophic a) Were the mutations in the same gene? b) Write the genotypes c) What progeny do you expect from crossing the mutants? Leu1- with Leu2- = wt, so mutations not in same gene "Parents" Leu1-; Leu2+ x Leu1+; Leu2- Progeny Leu1-; Leu2- = auxotroph Leu1-; Leu2+ = auxotroph Leu1+; Leu2- = auxotroph Leu1+; Leu2+ = prototroph
Added by Ivan O.
Close
Step 1
He combined them into a heterokaryon and found that it was prototrophic, indicating that the mutations were not in the same gene. Show more…
Show all steps
Your feedback will help us improve your experience
Suman K and 69 other Biology educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
You are co-infecting E. coli K(lambda) with two independent rII mutants and find that there is no plaque formation. This means that: a) no recombination occurs between the two mutations b) the two rII mutants are different genes, one in rIIA and the other in rIIB c) the two rII mutants are in the same rII gene, either rIIA or rIIB d) one of the mutants is dominant
Shaiju T.
Several auxotrophic point mutants in Neurospora are treated with various agents to see if reversion will take place. The following results were obtained (a plus sign indicates reversion; HA causes only $G \cdot C \rightarrow A \cdot T$ transitions). a. For each of the five mutants, describe the nature of the original mutation event (not the reversion) at the molecular level. Be as specific as possible. b. For each of the five mutants, name a possible mutagen that could have caused the original mutation event. (Spontaneous mutation is not an acceptable answer.) c. In the reversion experiment for mutant $5,$ a particularly interesting prototrophic derivative is obtained. When this type is crossed with a standard wild-type strain, the progeny consist of 90 percent prototrophs and 10 percent auxotrophs. Give a full explanation for these results, including a precise reason for the frequencies observed.
A mutation results in the formation of the mutated maturemRNA as indicated in the diagram. Describe what type of mutation occurred and what the likely outcome of the mutation is. a. Mutation in the GU-AG sites of introns produced a non-functional protein. b. A transversion mutation in the introns led to alternative splicing, producing a functional protein. c. A transversion mutation in the GU-AG site mutated this mRNA, producing a non-functional protein. d. Transition mutations in the introns could produce a functional protein.
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD