Section 3: Genetics, Cellular and Molecular Biology
DNA replication, transcription, translation
Subtopic: Fundamentals of DNA replication, transcription, translation
Question Statement:
All pseudogenes DO NOT code for a ________.
Options:
(A) protein with original function
(B) protein with altered function
(C) RNA with coding sequence
(D) RNA with regulatory function
Official Answer Key:
A
Step-by-Step Solution & Explanation
### **Official Solution & Concept Analysis (GATE BT 2024 Q.27)**
**1. Governing Concept**:
- **Topic**: Molecular Genetics & Pseudogene Classification
- **Pseudogenes** are non-functional genomic DNA sequences that resemble functional genes but have acquired deleterious mutations (premature stop codons, frameshifts, promoter deletions).
- By definition, all pseudogenes **do not code for a protein with original function**, as the accumulation of mutations abolishes the original wild-type enzymatic or structural activity. Some pseudogenes may still be transcribed into regulatory non-coding RNAs or truncated peptides, but none retain the original gene's function.
**2. Option Analysis**:
- **Option (A) [protein with original function] is CORRECT**: Loss of original protein function is the universal defining hallmark of all pseudogenes.
- **Option (B) is INCORRECT**: Some pseudogenes or neofunctionalized retrocopies can acquire altered activities.
- **Option (C) is INCORRECT**: Many pseudogenes retain coding sequence remnants in transcribed RNA.
- **Option (D) is INCORRECT**: Many pseudogenes are actively transcribed into regulatory long non-coding RNAs or competing endogenous RNAs (ceRNAs).
**3. Final Answer**:
- **Correct Choice**: **A**
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