NEETZoologyPrinciples of Inheritance and Variation
Consider a normal male grasshopper and a normal male peacock. Which of the following correctly describes the sex chromosomal composition of the sperms produced by them?
Options
- AThe grasshopper produces 50% sperms with an X chromosome and 50% with a Y chromosome, while the peacock produc
- BThe grasshopper produces 50% sperms with an X chromosome and 50% with no sex chromosome, while the peacock pro
- CBoth the grasshopper and the peacock produce two different types of sperms, exhibiting male heterogamety.
- DThe grasshopper produces 50% sperms with an X chromosome and 50% with no sex chromosome, while the peacock pro
Correct answer
D. The grasshopper produces 50% sperms with an X chromosome and 50% with no sex chromosome, while the peacock pro
Step-by-step solution
The grasshopper follows the XX-XO mechanism of sex determination. A normal male grasshopper has an XO sex chromosome constitution. During spermatogenesis, 50% of the sperms receive an X chromosome and the other 50% receive no sex chromosome. The peacock (a bird) follows the ZW-ZZ mechanism of sex determination. A normal male peacock has a ZZ sex chromosome constitution (male homogamety). Therefore, 100% of the sperms produced by a male peacock will carry a Z chromosome. Thus, the grasshopper exhibits male heterogam