Question

In Drosophila sex is determined by

• A. X and Y chromosomes
• B. Ratio of pairs of X-chromosomes to the pairs of autosomes
• C. Ratio of number of X-chromosomes to the sets of autosomes
• D. Whether the egg is fertilized or develops parthengenetically

Answer 1

The correct option is C Ratio of number of X-chromosomes to the sets of autosomes

Calvin Bridges demonstrated that in Drosophila, the sex is determined by the ratio of the number of X-chromosomes to the sets of autosomes. According to genic balance theory of sex-determination, Y-chromosome of Drosophila does not important for the determination of sex.

So, the correct answer is 'Ratio of number of X-chromosomes to the sets of autosomes'.