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Question #46412
The Question
The fundamental principle of DNA fingerprinting relies on the premise that DNA from every tissue of an individual shows the same degree of polymorphism. However, in rare instances, the VNTR (Variable Number of Tandem Repeats) banding pattern from an individual's blood sample slightly differs from that of their skin cells. Assuming no technical errors, which of the following is the most scientifically accurate explanation for this phenomenon?
Options
- A.
A post-zygotic somatic mutation occurred in the hyper-variable repetitive DNA during embryonic development.
- B.
Differential gene expression alters the VNTR length in mesodermal tissues compared to ectodermal tissues.
- C.
The absence of a nucleus in mature erythrocytes results in a truncated DNA fingerprint in the blood sample.
- D.
Alternative splicing of the repetitive DNA sequences varies between different somatic cell lineages.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
VNTR|Restriction Endonucleases|Gel Electrophoresis
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the NCERT line 'DNA from every tissue is identical' as an absolute dogma, failing to account for the biological reality that VNTRs have exceptionally high mutation rates.
A post-zygotic mutation creates somatic mosaicism, challenging the 'universal fingerprint' assumption.
The distractors exploit common confusions between the genome (DNA sequence) and the transcriptome (RNA expression/splicing), as well as the classic 'RBCs lack nuclei' trap.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Molecular Basis of Inheritance - Class 12 |
| Concept | Human Genome Repetitive DNA |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |