MHT CET 202622 AprilEvening Shift
- Exam
- MHT CET
- Year
- 2026
- Date
- 22 April
- Shift
- Evening Shift
- Subject
- Biology
- Chapter
- Principles of Inheritance and Variation
MHT CET 2026 · 22 April · Evening Shift · Biology · Principles of Inheritance and Variation
In X and Y chromosomes, crossing over occurs only between ____.
In X and Y chromosomes, crossing over occurs only between ____.
Options
- Ahomologous regions of both X and Y
- Bnon-homologus regions of both X and Y
- Cnon-homologous region of X and homologous region of Y
- Dhomologous region of X and non-homologous region of Y
Correct answer
A. homologous regions of both X and Y
Step-by-step solution
The X and Y chromosomes are structurally different but share short regions of homology known as pseudoautosomal regions (PARs) at their tips.
During meiosis in males, the X and Y chromosomes pair up and undergo crossing over (recombination) exclusively within these homologous regions.
The non-homologous regions of the X and Y chromosomes do not undergo crossing over, which prevents the exchange of sex-determining genes (like the SRY gene on the Y chromosome).
Therefore, crossing over occurs only between the homologous regions of both X and Y chromosomes.
Answer: homologous regions of both X and Y
During meiosis in males, the X and Y chromosomes pair up and undergo crossing over (recombination) exclusively within these homologous regions.
The non-homologous regions of the X and Y chromosomes do not undergo crossing over, which prevents the exchange of sex-determining genes (like the SRY gene on the Y chromosome).
Therefore, crossing over occurs only between the homologous regions of both X and Y chromosomes.
Answer: homologous regions of both X and Y