Question

Given below are two statements, one is labelled as Assertion (A) and other labelled as Reason (R).
Assertion (A): During meiosis, genetic recombination occurs which leads to genetic diversity among offspring.
Reason (R): Genetic recombination is facilitated by the crossing over of homologous chromosomes during prophase I of meiosis.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A).
• B. Both (A) and (R) are correct but (R) is NOT the correct explanation of (A).
• C. (A) is correct but (R) is not correct.
• D. (A) is not correct but (R) is correct.

Hint:

To verify Assertion-Reason questions, connect them with "because":
"Genetic recombination occurs during meiosis... because crossing over of homologous chromosomes takes place in prophase I."
This confirms that the Reason is the direct mechanism behind the Assertion.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Meiosis is a specialized cell division process that reduces the chromosome number by half, producing four genetically diverse haploid daughter cells.
Genetic recombination during meiosis is a primary source of genetic variation in sexually reproducing organisms.

Step 2: Detailed Explanation:
Let us analyze the relationship between the Assertion and the Reason:
- Assertion (A): During meiosis, genetic material is reshuffled, which results in offspring with unique combinations of alleles.
This ensures genetic diversity within populations, which is essential for evolution and adaptation.
Thus, Assertion (A) is correct.
- Reason (R): During prophase I of meiosis, homologous chromosomes pair up (synapsis) to form bivalents.
Non-sister chromatids of these homologous chromosomes can break and swap corresponding segments at contact points called chiasmata.
This physical exchange of genetic material is known as crossing over.
Crossing over disrupts existing linkage groups and creates new recombinant chromatids.
Thus, Reason (R) is correct.
Since the physical crossing over of homologous chromosomes during prophase I is the specific cellular mechanism that drives the genetic recombination described in the Assertion, the Reason directly explains why genetic recombination occurs.
Therefore, both statements are correct, and (R) is the correct explanation of (A).

Step 3: Final Answer:
Both (A) and (R) are correct and (R) is the correct explanation of (A).