NEETZoologyPrinciples of Inheritance and Variation
In a particular animal species, the somatic cells of both males and females contain the exact same total number of chromosomes. During gametogenesis, females produce two distinct types of gametes in equal proportion, whereas males produce only one type of gamete. Based on this information, identify the animal and its corresponding sex-determination mechanism.
Options
- APeacock; ZZ-ZW type
- BGrasshopper; XX-XO type
- CDrosophila; XX-XY type
- DHuman; XX-XY type
Correct answer
A. Peacock; ZZ-ZW type
Step-by-step solution
The problem states that females produce two distinct types of gametes while males produce only one type. This indicates female heterogamety and male homogamety. The fact that both sexes have the same total number of chromosomes rules out the XX-XO mechanism (where males have one less chromosome than females). This points to the ZZ-ZW sex-determination system, where females are ZW (producing Z and W bearing eggs) and males are ZZ (producing only Z bearing sperms). Among the given options, birds such as the peacock e