Which F1 genotype represents a female that does not have red eyes in a cross between two specific fly genotypes?

Which F1 genotype represents a female that does not have red eyes in a cross between two specific fly genotypes?

• A. CCXw-eY
• B. CcaXw-eXw-e
• C. CcaXw+Xw-e
• D. CcaXw+Y

Answer: (B)

In this genetic context, the focus is on the inheritance patterns of the eye color trait in fruit flies. The alleles involved can be represented as follows: the allele for red eyes (often symbolized as Xw+) and the allele for non-red eyes (represented as Xw-e). In a typical Drosophila genetic cross, females need a combination of alleles on their X chromosomes since females possess two X chromosomes, while males have one X and one Y chromosome. For a female to not exhibit red eyes, she must inherit at least one copy of the non-red allele (Xw-e) on both of her X chromosomes. The genotype provided as the correct answer, which is CcaXw-eXw-e, includes two copies of the Xw-e allele (one from each X chromosome). This means that the female represented by this genotype will not produce red eyes, as she lacks the dominant Xw+ allele necessary for red-eyed phenotype expression. The other genotypes do not fulfill the requirement for a phenotype with non-red eyes, as they either express the red eye genotype or only possess one copy of the non-red eye allele. Thus, the selected genotype properly portrays a female that lacks red eyes due to the presence

In this genetic context, the focus is on the inheritance patterns of the eye color trait in fruit flies. The alleles involved can be represented as follows: the allele for red eyes (often symbolized as Xw+) and the allele for non-red eyes (represented as Xw-e).

In a typical Drosophila genetic cross, females need a combination of alleles on their X chromosomes since females possess two X chromosomes, while males have one X and one Y chromosome. For a female to not exhibit red eyes, she must inherit at least one copy of the non-red allele (Xw-e) on both of her X chromosomes.

The genotype provided as the correct answer, which is CcaXw-eXw-e, includes two copies of the Xw-e allele (one from each X chromosome). This means that the female represented by this genotype will not produce red eyes, as she lacks the dominant Xw+ allele necessary for red-eyed phenotype expression.

The other genotypes do not fulfill the requirement for a phenotype with non-red eyes, as they either express the red eye genotype or only possess one copy of the non-red eye allele. Thus, the selected genotype properly portrays a female that lacks red eyes due to the presence