Question

Male heterogamy is not present in:

• A. Human
• B. Grasshopper - XO
• C. Drosophila - XY
• D. Honey bee - haploid-diploid

Hint:

Important sex-determination systems: \[ \boxed{ \begin{aligned} XY &\rightarrow \text{Human, Drosophila}\\ XO &\rightarrow \text{Grasshopper}\\ ZW &\rightarrow \text{Birds}\\ \text{Haplodiploid} &\rightarrow \text{Honey bee} \end{aligned} } \] Honey bees determine sex by chromosome number rather than sex chromosomes.

Answer 1

The Correct Option is D

Concept: Heterogamety refers to the condition in which one sex produces two different types of gametes with respect to sex chromosomes. Male heterogamety is observed in: \[ \boxed{ \begin{aligned} XY &\rightarrow \text{Human, Drosophila}\\ XO &\rightarrow \text{Grasshopper} \end{aligned} } \] In honey bees, sex determination follows the haplodiploid system rather than the XY or XO mechanism.

Step 1: Understand male heterogamety.
A heterogametic male produces two kinds of sperms. Examples: \[ \boxed{ \begin{aligned} XY &\rightarrow X\text{ and }Y\text{ sperms}\\ XO &\rightarrow X\text{ and }O\text{ sperms} \end{aligned} } \]

Step 2: Analyse each option.

• Humans possess the XY system.

• Grasshoppers possess the XO system.

• Drosophila also has the XY system.

• Honey bees exhibit haplodiploid sex determination, where males are haploid (\(n\)) and females are diploid (\(2n\)).
Thus, honey bees do not exhibit male heterogamety.

Step 3: Choose the correct option.
Therefore, \[ \boxed{\textbf{Option (D)}} \] is the correct answer.