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?

[UPSC Civil Services Exam – 2021 Prelims]

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2


Answer: (c)        

Explanation:

Mitochondrial replacement therapy (MRT)

  • It is a type of in vitro fertilization (IVF) that involves the replacement of a woman’s unhealthy mitochondrial DNA (mtDNA) with healthy mtDNA from a donor. Various techniques are used for MRT, including spindle transfer (ST), pronuclear transfer (PNT), and polar body transfer (PBT).
  • Pronuclear transfer is an MRT technique that involves fertilizing two zygotes in vitro.
  • Maternal spindle transfer (MST) is an MRT technique that involves selective reproduction similar to prenatal diagnosis and pre-implantation genetic diagnosis (PGD) and is carried out before fertilization. Statement 1 is correct.

Mitochondria

  • Mitochondria are the only organelles, besides the nucleus, that contain circular DNA and genes in animals. However, sperm contains a minimal amount of mitochondria and mitochondrial genes. As a result, mitochondrial genes are solely inherited from the mother by the offspring. This means that a father with a mitochondrial gene defect cannot pass the condition onto his children. Statement 2 is correct.

Consider the following statements:                                                                   The Parliament of India can place a particular law in the Ninth Schedule of the Constitution of India. The validity of a law placed in the Ninth Schedule cannot be examined by any court and no judgement can be made on it. Which of the statements given above is/are correct?

Consider the following statements:                                               

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Consider the following statements:                                                         The Parliament of India can place a particular law in the Ninth Schedule of the Constitution of India. The validity of a law placed in the Ninth Schedule cannot be examined by any court and no judgement can be made on it. Which of the statements given above is/are correct?

Consider the following statements:                                               

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