Exam 1 - Fall 2023

3 3. You now want to organize your mutants into complementation groups. By inducing sporulation, you are able to generate the same 18 Leu-mutants with the a-mating type. Below are the results of a portion of the complementation assay you performed to begin to characterize these mutants. Answer the following questions: (16 points) a. Place these 8 Leu- mutants into complementation groups. (8 points) b. How many different Leucine genes were isolated? (1 point) c. Does one of these groups demonstrate intragenic complementation? Why or why not? (1 point) d. If Mutant 1 had been a defective mater, what would row two look like? (1 point) e. If Mutant 8 had actually been Leu+, what would row four look like? (1 point) f. You now determine the DNA sequence of the mutated leu genes in each of your mutants. What is the most likely type of mutation you would expect to find for Mutant 4 ? (circle 1 answer) (2 pts) a) deletion b) insertion c) frameshift mutation c) missense mutation d) nonsense mutation g. Assume that there are actually a total of five different Leu genes. Which of the following matings would complement each other and grow on Leu- media? (circle all correct) (4 points) a) TD28 ( MAT α Leu1 ) and TD28 ( MATa Leu3 ) b) TD28 ( MAT α Leu2 ) and TD28 ( MATa Leu2 ) c) TD28 ( MATa Leu3 ) and TD28 ( MAT α Leu5 ) d) TD28 ( MAT α Leu5 ) and TD28 ( MATa Leu2 ) e) TD28 ( MATa Leu4 ) and TD28 ( MAT α Leu1 ) f) TD28 ( MATa Leu3 ) and TD28 ( MATa Leu5 ) g) TD28 ( MAT α Leu4 ) and TD28 ( MAT α Leu5 ) h) TD28 ( MATa Leu4 ) and TD28 ( MAT α Leu4 )

6 8. You perform reciprocal crosses between Drosophila melanogaster strains 1 and 2. These two strains (1 and 2) breed true for their respective mutant traits. (15 points) Strain 1 has the mutant traits: red wing veins, bent antennae, pink body Strain 2 has the mutant traits: long bristles, small eyes You score 500 flies from each cross . Below are the mutant phenotypes of the F1 progeny as a result of each of the reciprocal crosses: Po: Strain 1 male X Strain 2 female F1 Males F1 Females Long bristles, small eyes, red wing veins 241 2 Small eyes, red wing veins 0 257 Po: Strain 2 male X Strain 1 female F1 Males F1 Females Red wing veins, small eyes 0 253 Red wing veins 247 0 Based on this information, state whether each of the mutant phenotypes behave as an autosomal or sex- linked, dominant or recessive trait. Also provide a brief rationale for your conclusion. 1. Red wing veins: Rationale: 2. Bent antennae is: Rationale: 3. Long bristles is: Rationale: 4. Small eyes is: Rationale: 5. Pink body is: Rationale: