Minimalist IAS
Prelims 2021 paper

UPSC CSE Prelims 2021 · GS Paper I · Question 66 · Biotechnology & genetics

आनुवंशिक रोगों के संदर्भ में, निम्नलिखित कथनों पर विचार कीजिए :

UPSC Civil Services (Preliminary) Examination 2021, General Studies Paper I, Question 66 — Biotechnology & genetics.

Prelims 2021 · Q66

Biotechnology & genetics Medium

आनुवंशिक रोगों के संदर्भ में, निम्नलिखित कथनों पर विचार कीजिए :

  1. 1.अंडों के अंतःपात्र (इन विट्रो) निषेचन से या तो पहले या बाद में सूत्रकणिका प्रतिस्थापन (माइटोकॉन्ड्रिअल रिप्लेसमेंट) चिकित्सा द्वारा सूत्रकणिका रोगों (माइटोकॉन्ड्रिअल डिजीज) को माता-पिता से संतान में जाने से रोका जा सकता है।
  2. 2.किसी संतान में सूत्रकणिका रोग आनुवंशिक रूप से पूर्णतः माता से जाता है न कि पिता से।

उपर्युक्त कथनों में से कौन-सा/कौन-से सही है/हैं?

Read this question in English

In the context of hereditary diseases, consider the following statements:

1. Passing on mitochondrial diseases from parent to child can be prevented by mitochondrial replacement therapy either before or after in vitro fertilization of egg.

2. A child inherits mitochondrial diseases entirely from mother and not from father.

Which of the statements given above is/are correct?

(a) 1 only · (b) 2 only · (c) Both 1 and 2 · (d) Neither 1 nor 2

उत्तर और व्याख्या · explanation in English

Answer: (c) 1 और 2 दोनों

Both statements are correct: mitochondrial DNA comes only from the mother's egg, and mitochondrial replacement therapy swaps the faulty mitochondria either before fertilisation (spindle transfer) or after it (pronuclear transfer).

  • ✓ 1. Two techniques are used: in maternal spindle transfer the mother's nuclear genetic material is moved into a donor egg before fertilisation, and in pronuclear transfer the fertilised embryo's nuclear material is moved into a donor embryo after fertilisation. Either way the child gets healthy donor mitochondria.
  • ✓ 2. Only egg cells contribute mitochondria to the embryo, so only females pass on mitochondrial DNA variants; a father's sperm does not pass them on.

Remember · Mitochondrial DNA is inherited only from the mother. Mitochondrial replacement therapy: spindle transfer (before fertilisation) or pronuclear transfer (after fertilisation).

Sources

Question and answer: UPSC's official GS Paper I (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·

Cite this question: UPSC CSE Prelims 2021, Q66 — minimalistias.com/pyqs/prelims/2021/q66

In the UPSC syllabus: Biotechnology & genetics › Stem cells, cloning & new therapies See it and tick it covered →

Timed · 30 minutes Take Science & technology · Set 5 as a test This question is in it — with UPSC's marking and an instant score. Start the set Or the whole 2021 paper →

More on Biotechnology & genetics

All Biotechnology & genetics questions →

Same topic in the Mains syllabus