Question

Assume that you are told that a particular organism, Drosophila, has the XO chromosome complement. You are also told that the autosomal complement is a normal 2n. You know that in humans the XO complement is female determining. Would you be correct in assuming that the Drosophila sex for XO is also female? Choose the answer that includes the correct explanation.

1) Yes, because sex determination in humans and insects is essentially the same.
2) No, sex determination in Drosophila is dependent on the presence or absence of the Y chromosome.
3) No, the chromosomal basis for sex determination in Drosophila based on the balance between the number of X chromosomes and haploid sets of autosomes.

Answer 1

The XO chromosome complement in Drosophila does not determine the sex as female, as it does in humans. Instead, it is the balance between the number of X chromosomes and autosomes that determines sex in Drosophila.

Step-by-step explanation:

No, the chromosomal basis for sex determination in Drosophila is based on the balance between the number of X chromosomes and haploid sets of autosomes. In Drosophila, females have two X chromosomes (XX) and males have one X chromosome (XO). The XO chromosome complement in Drosophila does not determine the sex as female, as it does in humans. Instead, it is the balance between the number of X chromosomes and autosomes that determines sex in Drosophila.