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Assuming a normal number of autosomes, what would be the sex of the following: XXY mouse,

XXY Drosophila?
A) female and female, respectively
B) male and male, respectively
C) both neuter
D) female and male, respectively
E) male and female, respectively

User Nayburz
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Final answer:

The XXY mouse would be male due to the presence of a Y chromosome triggering male development, while the XXY Drosophila would be female based on the X:A ratio. Hence, the answer is D) female and male, respectively.

Step-by-step explanation:

The sex of an organism in mammals, including mice, is determined by the presence of sex chromosomes. Females typically have two X chromosomes (XX), and males have one X and one Y chromosome (XY). However, due to a nondisjunction event during meiosis, an individual can end up with an extra chromosome, such as XXY.

For mice, which are mammals, having an XXY combination of sex chromosomes results in a condition known as Klinefelter syndrome. Individuals with this chromosomal arrangement are phenotypically male because they possess a Y chromosome that triggers the development of male characteristics.

In Drosophila, also known as fruit flies, the presence of Y chromosome does not determine maleness. Instead, the ratio of the number of X chromosomes to the number of sets of autosomes (X:A ratio) is responsible for sex determination. A ratio of 1.0 is typically female, while a ratio of 0.5 is male. An XXY Drosophila would likely have an X:A ratio of 1.0, which would result in a female phenotype.

Therefore, the answer to the student's question is D) female and male, respectively. The XXY mouse is male due to the presence of the Y chromosome, while the XXY Drosophila is female because of the X:A ratio.

User Sbirch
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