It is known that in Drosophila and in humans, the male gender is determined by the XY chromosomes, and the female – XX

It is known that in Drosophila and in humans, the male gender is determined by the XY chromosomes, and the female – XX. In this case, with the XXY genotype, Drosophila will be a female, and a man – a man. Explain this phenomenon.

1) In humans, the main factor affecting the determination of sex is the presence of the U chromosome. If it is, the body has a male gender. Even if there are three or four X-chromosomes in the genome, but, in addition, at least one Y-chromosome, then a man develops from such a zygote.
2) The fact is that Drosophila has very few genes in the Y chromosome, and these are genes that are responsible for the development of sperm in an adult male. On the contrary, in a person in the short arm of the Y chromosome lies the S gene, which plays a crucial role in determining sex. It encodes a protein that switches the body from the female path to the male. This gene plays a decisive role in other mammals, but Drosophila does not have such a gene, therefore, CLC will be a female, because the X chromosome predominates