Concept:The mechanisms of sex determination vary between species. Humans rely on the Y chromosome to dictate maleness, while
Drosophila rely on the ratio of X chromosomes to autosomes.
Solution:- The chromosomal genotype XO (having only one X chromosome and lacking a second sex chromosome) produces distinct outcomes across species.
- In Humans: The lack of a Y chromosome defaults development to female. However, lacking the second X chromosome causes Turner's syndrome, resulting in a sterile female.
- In Drosophila: The X to autosome ratio dictates sex. An XO fly develops physically as a male, but because it lacks the necessary sperm-motility genes located on the Y chromosome, it is entirely sterile.
Why other options are incorrect:- XXY: In humans, this causes Klinefelter syndrome (sterile male). In Drosophila, it results in a fertile female.
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