Question

Match the LIST-I with LIST-II

Choose the correct answer from the options given below:

• A. A-I, B - II, C - III, D - IV
• B. A-II, B-I, C - III, D - IV
• C. A-I, B-II, C - IV, D - III
• D. A-II, B-I, C - IV, D - III

Hint:

Break down the prefixes: \textbf{Nulli-} (none, zero) \(\rightarrow\) a whole pair is gone. \textbf{Mono-} (one) \(\rightarrow\) one chromosome is gone. \textbf{Auto-} (self) \(\rightarrow\) multiple genomes from the same species. \textbf{Allo-} (other) \(\rightarrow\) multiple genomes from different species.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
This question tests the terminology for different types of chromosomal number variations, including aneuploidy (loss or gain of individual chromosomes) and polyploidy (presence of extra sets of chromosomes).
Step 2: Detailed Explanation:
Let's match each term with its correct definition:


A. Nullisomic: This is a form of aneuploidy where a complete homologous pair of chromosomes is lost. The chromosomal composition is represented as (2n - 2). This matches II. One chromosome pair missing.

B. Monosomic: This is a form of aneuploidy where a single chromosome from a homologous pair is lost. The composition is (2n - 1). This matches I. One chromosome missing.

C. Allotetraploid: This is a form of polyploidy where an organism contains four sets of chromosomes derived from two or more different species. For example, if species 1 has genome A and species 2 has genome B, an allotetraploid would be AABB. This matches IV. Two distinct genomes; each has two copies.

D. Autotetraploid: This is a form of polyploidy where an organism has four sets of chromosomes, all derived from a single species. For example, if the basic genome is A, an autotetraploid would be AAAA. This matches III. Four copies of the same genome present.

Step 3: Final Answer:
The correct matching is A-II, B-I, C-IV, D-III.