Question

Select the incorrect statement.

• A. Male fruit fly is heterogametic.
• B. In male grasshoppers, 50% of sperms have no sex-chromosome.
• C. In domesticated fowls, sex of progeny depends on the type of sperm rather than egg.
• D. Human males have one of their sex-chromosome much shorter than the other.

Answer 1

The Correct Option is C

This question tests your knowledge about sex determination systems in different species. Let's go through each statement to determine which is incorrect.

1. Male fruit fly is heterogametic.
   The fruit fly (Drosophila melanogaster) uses the XY sex determination system, similar to humans. Here, the male is heterogametic, having one X and one Y chromosome.
   Explanation: It is a true statement.
2. In male grasshoppers, 50% of sperms have no sex-chromosome.
   Grasshoppers use the XO sex determination system, where males have only one X chromosome and no Y chromosome. Therefore, sperms produced by males have either an X chromosome or no sex chromosome.
   Explanation: The statement is correct as 50% of sperms have no sex chromosome (only autosomes are present).
3. In domesticated fowls, sex of progeny depends on the type of sperm rather than egg.
   In birds, including domesticated fowls, the sex determination system is ZW, where females are heterogametic (ZW) and males are homogametic (ZZ). The sex of the offspring is determined by the egg (female), not by the sperm (male).
   Explanation: This statement is incorrect because progeny sex is determined by the type of egg (Z or W) rather than sperm.
4. Human males have one of their sex chromosome much shorter than the other.
   In humans, males have one X and one Y chromosome. The Y chromosome is significantly shorter than the X chromosome.
   Explanation: This is a true statement.

Therefore, the incorrect statement is: In domesticated fowls, sex of progeny depends on the type of sperm rather than egg.