Question
R= red eyes; r= white eyes - parents are a homozygous white eyed female and a red eyed male
In fruit flies, the color of the eyes is sex linked (on the X chromosome). A cross of the flies in the image will produce
a
0% of the females with white eyes, 50% of the males with white eyes.
b
50% red eyed flies
c
0% white eyed flies
d
100% of the females with red eyes, 100% of the males with white eyes.
In fruit flies, the color of the eyes is sex linked (on the X chromosome). A cross of the flies in the image will produce
a
0% of the females with white eyes, 50% of the males with white eyes.
b
50% red eyed flies
c
0% white eyed flies
d
100% of the females with red eyes, 100% of the males with white eyes.
Answers
GPT-4o mini
In fruit flies, the allele for red eyes (R) is dominant, and the allele for white eyes (r) is recessive and sex-linked, meaning it is located on the X chromosome.
The given parental genotypes are:
- Homozygous white-eyed female: XᵖXᵖ (where Xᵖ denotes the X chromosome with the white eye allele)
- Red-eyed male: XᴿY (where Xᴿ denotes the X chromosome with the red eye allele)
When these two flies are crossed, the following gametes will be produced:
- The white-eyed female (XᵖXᵖ) can only produce Xᵖ gametes.
- The red-eyed male (XᴿY) can produce Xᴿ and Y gametes.
The potential offspring from this cross will be:
- Female offspring: Xᵖ (from the mother) and Xᴿ (from the father), resulting in XᵖXᴿ (which will exhibit red eyes since red is dominant).
- Male offspring: Xᵖ (from the mother) and Y (from the father), resulting in XᵖY (which will exhibit white eyes since the male has only one X chromosome).
Now, summarizing the results:
- 100% of the females will have red eyes (XᵖXᴿ).
- 100% of the males will have white eyes (XᵖY).
Given the answer choices:
- a) 0% of the females with white eyes, 50% of the males with white eyes.
- b) 50% red eyed flies.
- c) 0% white eyed flies.
- d) 100% of the females with red eyes, 100% of the males with white eyes.
The correct answer is:
**d) 100% of the females with red eyes, 100% of the males with white eyes.**
The given parental genotypes are:
- Homozygous white-eyed female: XᵖXᵖ (where Xᵖ denotes the X chromosome with the white eye allele)
- Red-eyed male: XᴿY (where Xᴿ denotes the X chromosome with the red eye allele)
When these two flies are crossed, the following gametes will be produced:
- The white-eyed female (XᵖXᵖ) can only produce Xᵖ gametes.
- The red-eyed male (XᴿY) can produce Xᴿ and Y gametes.
The potential offspring from this cross will be:
- Female offspring: Xᵖ (from the mother) and Xᴿ (from the father), resulting in XᵖXᴿ (which will exhibit red eyes since red is dominant).
- Male offspring: Xᵖ (from the mother) and Y (from the father), resulting in XᵖY (which will exhibit white eyes since the male has only one X chromosome).
Now, summarizing the results:
- 100% of the females will have red eyes (XᵖXᴿ).
- 100% of the males will have white eyes (XᵖY).
Given the answer choices:
- a) 0% of the females with white eyes, 50% of the males with white eyes.
- b) 50% red eyed flies.
- c) 0% white eyed flies.
- d) 100% of the females with red eyes, 100% of the males with white eyes.
The correct answer is:
**d) 100% of the females with red eyes, 100% of the males with white eyes.**