Quiz 2: Genetic Interactions (16 points)*Please review lecture 5A (genetic interaction) before attempting this quiz*Multiple choices. Only one correct answer per question*Please have pencil and scratch paper ready*Can be attempted twice before Oct. 2 (test ending Oct. 2 11:59 PM)* You have up to 45 minutes to work on this Quiz once you start1. A mutant Drosophila is showing enlarged head (bighead-recessive). Another Drosophila mutant is showing a smaller head (smallhead-recessive). Charles constructed double mutants that are homozygous for both bighead and smallhead mutations. He found that the smallhead mutation is epistatic to bighead. What is the double mutant phenotype? (assuming the two mutations act in a regulatory pathway).a. Bigheadb. Smallheadc. Normal size head2. Based on the observed double mutant phenotype, Charles concluded thata. Bighead gene acts earlier in the regulatory pathway to regulate the smallhead gene. b. Smallhead gene acts earlier in the regulatory pathway to regulate the bighead gene.c. The order of these two genes can not be resolved based on the data3. Charles isolated a third mutant that shows white eyes (wild type has red eye). He crossed white eye mutant with bighead, the double mutant showed both big head and white eye. What type of genetic interaction is this? a. White eye is epistatic to bigheadb. Bighead is epistatic to white eyec. White eye and bighead show additive interactiond, White eye and bighead are mutually suppressive4. Continue with question 3, If white eye is crossed into smallhead, what is the double mutant phenotype?a. white eye, normal headb. white eye, small headc. red eye, small headA B C5. The biosynthesis pathway of plant hormone auxin is shown below. A, B, and C genes encode enzymes that catalyze each of the step drawn. Without auxin, the plant can’t set fruit. Trp -------> IPA ------- IAID ------- auxinIn a mutant defective in auxin biosynthesis, no fruit was set. Dr. Liu decided to grow the mutant in a medium supplemented with Trp. Still, no fruit was set. She then added IPA to the medium, the plant was able to set fruit. The above mutant is defective in which gene of the auxin biosynthesis pathway? a. A geneb. B genec. C gene6. (Continue with question 5) Which chemical precursor does mutant A accumulate? a. Trpb. IPAc. IAID7. (Continue with question 5) In the AB double mutant (defective in both gene A and B), which chemical precursor does AB double mutant accumulate?a. Trpb. IPAc. IAID8. Based on your answer to question 7, what type of genetic interaction is there between A and B mutation?a. A is epistatic to Bb. B is epistatic to Ac. A and B are
View Full Document
Unlocking...