Biology - Principles of Inheritance and Variation Question with Solution | TestHub
BiologyPrinciples of Inheritance and VariationChromosomal Theory of Inheritance and LinkageMedium2 minPYQ_2026
BiologyMediumsingle choice
In X and Y chromosomes, crossing over occurs only between ____.
Options:
Answer:
A
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
Stream:MHT_CET_MEDICALSubject:BiologyTopic:Principles of Inheritance and VariationSubtopic:Chromosomal Theory of Inheritance and Linkage
⏱ 2mℹ️ Source: PYQ_2026
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