Question

UPSC Prelims 2020 Question:

In the context of recent advances in human reproductive technology, "Pronuclear Transfer" is used for

  1. 1. fertilization of egg in vitro by the donor sperm
  2. 2. genetic modification of sperm producing cells
  3. 3. development of stem cells into functional embryos
  4. 4. prevention of mitochondrial diseases in offspring

Answer (Detailed Solution Below)

Option 4: prevention of mitochondrial diseases in offspring

Detailed Solution

Explanation:

  • Mutations in mitochondrial DNA (MtDNA) are a common cause of genetic diseases. Patients with MtDNA disease have extremely limited treatment options, which are mostly supportive in nature. MtDNA is transmitted maternally, and nuclear transfer techniques have been proposed as a method of preventing the transmission of human mitochondrial disease.

  • In pronuclear transfer, a zygote is formed by first fertilising the mother's egg with the father's sperm. The donor egg is then fertilised and has its own nucleus removed. The pro-nuclei of the egg and sperm are then extracted from the zygote and put into the donor egg (a pronucleus is the nucleus of the egg or sperm at the stage of fertilisation prior to nucleus fusion). 

  • The zygote derived from the donor egg is then implanted into the mother’s uterus. It is thus used in the process of three-parent baby. In Three-parent baby, human offspring is produced from the genetic material of one man and two women through the use of assisted reproductive technologies, specifically mitochondrial manipulation (or replacement) technologies and three-person in vitro fertilisation (IVF).

Therefore, option (4) is the correct answer.

Subject: Science & Technology | Biotechnology

Latest UPSC Exam 2026 Updates

Last updated on March, 2026

UPSC Final Result 2025 is now out.

→ UPSC has released UPSC Toppers List 2025 with the Civil Services final result on its official website.

Anuj Agnihotri secured AIR 1 in the UPSC Civil Services Examination 2025.

UPSC Marksheet 2025 is now out.

UPSC Notification 2026 & UPSC IFoS Notification 2026 is now out on the official website at upsconline.nic.in.

UPSC Calendar 2026 has been released.

→ Check out the latest UPSC Syllabus 2026 here.

UPSC Prelims 2026 will be conducted on 24th May, 2026 & UPSC Mains 2026 will be conducted on 21st August 2026.

→ The UPSC Selection Process is of 3 stages-Prelims, Mains and Interview.

→ Prepare effectively with Vajiram & Ravi’s UPSC Prelims Test Series 2026 featuring full-length mock tests, detailed solutions, and performance analysis.

→ Enroll in Vajiram & Ravi’s UPSC Mains Test Series 2026 for structured answer writing practice, expert evaluation, and exam-oriented feedback.

→ Join Vajiram & Ravi’s Best UPSC Mentorship Program for personalized guidance, strategy planning, and one-to-one support from experienced mentors.

Shakti Dubey secures AIR 1 in UPSC CSE Exam 2024.

→ Also check Best UPSC Coaching in India

Vajiram Content Team
Vajiram Content Team
UPSC GS Course 2026
UPSC GS Course 2026
₹1,75,000
Enroll Now
GS Foundation Course 2 Yrs
GS Foundation Course 2 Yrs
₹2,45,000
Enroll Now
UPSC Mentorship Program
UPSC Mentorship Program
₹85000
Enroll Now
UPSC Sureshot Mains Test Series
UPSC Sureshot Mains Test Series
₹19000
Enroll Now
Prelims Powerup Test Series
Prelims Powerup Test Series
₹8500
Enroll Now
Enquire Now