In: Biology
In lab you are going to be using drosophila flies with sepia mutations (SE, se) causing brown eyes found on chromosome 3 and apterous mutation (AP, ap) on chromosome 2 causing loss of wings. These are recessive mutations. Red eye is the wild-type phenotype. Assuming you have a female heterozygous at both loci. Draw the chromosomes as they go through meiosis (Make sure you show somatic cell, prophase I, metaphase I, metaphase II, gametes.) Draw all possible gametes. What percentage of each phenotype do you expect? What are all the possible phenotypes and genotypes would you expect? This female mates with a male that is also heterozygous at both loci and they have 1000 progeny.
1. What are all possible phenotypes you could recover?
A. Red eyes and wings OR Red eyes and no wings
B. Red eyes and wings OR Brown eyes and no wings
C. Red eyes and wings OR Brown eyes and wings
D. Red eyes and wings OR Brown eyes and wings OR Red eyes and no wings
E. Red eyes and wings OR Brown eyes and wings OR Red eyes and no wings OR Brown eyes AND no wings
2. What combination of phenotypes is displayed the most?
A. Red eyes and wings
B. Red eyes and no wings
C. Brown eyes and wings
D. Brown eyes and no wings
3. Out of 1000 progeny how many animals would have the most common combination of phenotypes?
Numeric Answer:
4. What combination of phenotypes is displayed the least?
A. Red eyes and wings
B. Red eyes and no wings
C. Brown eyes and wings
D. Brown eyes and no wings
5. Out of 1000 progeny how many animals would have the least common combination of phenotypes?
Numeric Answer:
6. What is the least probable genotype?
A. SE/se; AP/ap
B. se/se; ap/ap
C. SE/SE; AP/AP
D. SE/se; AP/AP
E. SE/se; ap/ap
7. What is the second least probable genotype?
A. SE/se; AP/ap
B. se/se; ap/ap
C. SE/SE; AP/AP
D. SE/se; AP/AP
E. SE/se; ap/ap
8. What percent of progeny will have the most common genotype?
A. 6.25
B. 12.5
C. 18.75
D. 25
E. None of the Above
9. You find a Red eye fly with wings. What is the probability this fly is homozygous SE/SE?
Word Answer:
10. You find a Red eye fly with wings. What animal could you cross this animal to, in order determine if its homozygous or heterozygous at the SE locus.
A. A Red eyed fly with wings
B. A Red eye fly with or without wings
C. A heterozygous Red eye fly with or without wings
D. A homozygous Red eye fly with or without wings
E. A brown eye fly with or without wings
11. What is the probability that this fly in male?
Word Answer:
Draw all possible gametes.
The genotype of this female would be = SE/se AP/ap
Phenotype of this female = Red eyes, winged
The possible gametes would be-
Mating of the heterozygous female fly with heterozygous male fly will result in the following offsprings. The phenotypes and genotypes are mentioned.
1. What are all possible phenotypes you could recover?
Answer: Option E; there are four possible phenotypes, as mentioned in the punnett square mentioned above.
2. What combination of phenotypes is displayed the most?
Answer: Option A; red eyes and wings. There are 8 out of 16 possible phenotypes of this combination. This accounts for 50% of the total phenotypes.
3. Out of 1000 progeny how many animals would have the most common combination of phenotypes?
Answer: The most common phenotype is red eyes and wings. The probability of this combination is 50% as mentioned in the previous question. So, out of 1000 there would be 500 offsprings with red eyes and wings.
4. What combination of phenotypes is displayed the least?
Answer: Option D; brown eyes and no wings is the least displayed phenotype. The probability of this phenotype is 1 out of 16 offsprings.