UPSC Prelims 2020 Q44: Science & Technology – Biotechnology & Genetics
- (a) 1 only
- (b) 2 and 3 only
- (c) 2 only
- (d) 1, 2 and 3
Answer: (d) 1, 2 and 3
Explanation
Human Genome Editing: Current Capabilities
| Statement | Claim | Verdict | Detail |
|---|---|---|---|
| 1 | Genetic changes in egg/sperm-producing cells | TRUE | Germline editing possible (changes heritable). CRISPR can modify germ cells. Currently under moratorium in most countries but technically possible. |
| 2 | Edit genome before birth (early embryo) | TRUE | Somatic editing in early embryos is feasible. He Jiankui (China) edited embryos 2018 (controversial). Early embryonic stage allows genome-wide changes. |
| 3 | Inject human pluripotent stem cells into pig embryo | TRUE | Chimera research: Human iPSCs injected into pig embryos to grow organs. Aims to create human organs in pigs for transplantation. On-going research. |
All three statements are correct. Answer: (d) 1, 2 and 3.
Answer: (d) 1, 2 and 3.
Why each option is right or wrong
- (a) Incorrect. Incomplete. Statements 2 and 3 are also correct.
- (b) Incorrect. Incomplete. Statement 1 is also correct.
- (c) Incorrect. Incomplete. Statements 1 and 3 are also correct.
- (d) CORRECT. All three are technically correct: germline editing, embryonic editing, and human-pig chimeras are feasible (though ethically contentious).
Key point
Genome editing 2020: (1) Germline editing possible but under moratorium globally. (2) Somatic embryonic editing demonstrated (He Jiankui case). (3) Human-pig chimeras in early research stages. All technically feasible; ethical/regulatory barriers apply.
Remember
Genetic changes CAN be introduced in gamete-producing cells (Statement 1 correct). A person's genome CAN be edited before birth at early embryonic stage (Statement 2 correct). Human induced pluripotent stem cells CAN be injected into pig embryos for chimera research (Statement 3 correct).
Common mistakes
- Confusing somatic editing (current cells, not heritable) with germline editing (heritable). Both are possible; germline is more restricted.
- Assuming He Jiankui was isolated case. Embryonic editing is technically possible; He was exceptional in actually doing it.
- Missing that chimera research raises questions: how human-like can pig organs become? Rights issues for semi-human organisms?
Exam tip
Gene editing tools: CRISPR-Cas9 (most common), TALENs, zinc fingers. Somatic therapy allowed in many countries; germline therapy banned or restricted (heritability + unknown long-term effects).
Sources
- CRISPR-Cas9 Development: Jennifer Doudna & Emmanuelle Charpentier
- He Jiankui - The Birth of Gene-Edited Twins (2018 case study)