Final answer:
In fruit flies, the wild type allele is dominant over the loss of function allele of the white gene, resulting in a wild type level of red eye pigment even when the fly only has one functional copy of the gene.
Step-by-step explanation:
In Drosophila, the wild-type eye color is red and is dominant to white eye color. When fruit flies have only one functional copy of the white gene, they still exhibit a wild type level of red eye pigment. This means that the wild type allele is dominant over the loss of function allele, and heterozygous flies are indistinguishable from homozygous wild type flies. Therefore, the correct answer is A) the wild type allele is dominant over the loss of function allele.
Eye color in Drosophila melanogaster (fruit flies) is an X-linked trait, and red eye color (symbolized as XW) is dominant to white eye color (symbolized as Xw). When a cross is made between a homozygous red-eyed female (XWXW) and a white-eyed male (XwY), all F1 offspring will exhibit red eyes. This is because the red eye allele is dominant, and males inherit the X chromosome from their mother.