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Correct Answer: that they are x-linked recessive.
the correct explanation for the inheritance of white eyes in fruit flies, as observed in the described experiment, is that the trait is x-linked recessive. this conclusion is drawn from a foundational experiment conducted by the geneticist thomas hunt morgan, who studied the inheritance patterns of eye color in drosophila melanogaster (fruit flies). morgan's experiments led him to discover that certain traits, such as eye color, are linked to specific chromosomes.
in the case of the white-eyed male fruit fly crossed with red-eyed females, the inheritance pattern of the offspring can elucidate the nature of the genetic trait. since the male fly has only one x chromosome (xy sex determination system), the presence of white eyes suggests that the gene for eye color is located on the x chromosome and is recessive. the females, having two x chromosomes (xx), typically display the dominant eye color, which is red in this instance.
when the white-eyed male (x^wy) mates with red-eyed females (x^rx^r), the offspring receive one x chromosome from the mother and either an x or y chromosome from the father. this results in female offspring with genotype x^rx^w (carriers of the white-eyed trait but displaying red eyes due to the dominant allele) and male offspring with genotype x^ry (red-eyed). if any female offspring were to receive the white-eyed allele from both parents, they would display white eyes, but this situation does not occur in the given scenario as the mother has only red-eye alleles.
as a result, all the female offspring in this experiment display red eyes, either as x^rx^r or x^rx^w, and half of the male offspring display red eyes (x^ry), while the other half inherit the x^w from the father and the y from him as well, displaying white eyes (x^wy). this pattern confirms the x-linked recessive nature of the white eye color trait. the fact that only males display the white eye phenotype in the f1 generation and females remain carriers unless they receive the recessive allele from both parents is characteristic of x-linked recessive traits.
understanding these genetic principles not only highlights the mechanisms behind eye color inheritance in fruit flies but also provides insights into how genetic traits can be linked to specific chromosomes and how they manifest differently in different genders due to the differences in chromosome composition (xx for females and xy for males). this experiment and its conclusions are fundamental examples of how genetic traits are passed through generations and how they can be mapped to specific locations on chromosomes, adhering to mendel's principles of inheritance.
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