Note: This chapter was removed from the NCERT curriculum in the 2022 rationalization. Retained here as reproductive biology concepts underpin wildlife conservation, IVF and assisted reproduction technology (ART), and reproductive health — all relevant to GS3 science & technology.

Why this chapter matters for UPSC: Reproductive biology is the scientific backbone of GS3 topics including assisted reproduction technology legislation (ART Regulation Act 2021), surrogacy law (Surrogacy Regulation Act 2021), animal cloning for livestock improvement, and ex-situ conservation of endangered species. Dolly the sheep and India's cloned buffalo "Garima" are standard Prelims data points.

PART 1 — Quick Reference Tables

Types of Reproduction at a Glance

Mode Parents Involved Fertilization Genetic Outcome Examples
Sexual — external Two Outside body (water) Offspring genetically unique Fish, frogs, most amphibians
Sexual — internal Two Inside female body Offspring genetically unique Reptiles, birds, mammals, humans
Asexual — budding One None Genetically identical (clone) Hydra
Asexual — binary fission One None Genetically identical Amoeba
Asexual — regeneration One None Genetically identical Planaria, starfish

Viviparous vs Oviparous vs Ovoviviparous

Category Definition Examples UPSC Relevance
Viviparous Give birth to live young; embryo develops inside mother Most mammals, dolphins, whales, bats Whale/dolphin conservation; marine mammal biology
Oviparous Lay eggs (fertilized internally or externally) Birds, reptiles, fish, insects; platypus (mammal exception) Sea turtle nesting, Olympic Games biology trivia; platypus as monotreme
Ovoviviparous Eggs hatch inside mother's body; live birth Some sharks (hammerhead), some snakes Marine biology; shark conservation

Key Biotechnology Milestones — Cloning & ART

Event Year Details UPSC Angle
Dolly the sheep cloned 1996 Roslin Institute, Scotland; first mammal cloned from adult somatic cell; technique: SCNT (Somatic Cell Nuclear Transfer) Standard Prelims fact
India's first IVF baby (Durga) 1978 Kolkata; Dr. Subhas Mukherjee; same year as Louise Brown (UK) Historical priority claim
World's first IVF baby 1978 Louise Brown, UK; Drs. Steptoe & Edwards (Nobel 2010) Nobel Prize context
Garima — India's first cloned animal 2009 Buffalo; NDRI (National Dairy Research Institute), Karnal, Haryana Prelims fact; NDRI location
Garima-II 2010 Second cloned buffalo; NDRI Follow-up milestone
ART Regulation Act 2021 Regulates IVF clinics, donor gametes, surrogates in India GS2/GS3 legislation
Surrogacy (Regulation) Act 2021 Allows only altruistic surrogacy; bans commercial surrogacy GS2/GS3 legislation

PART 2 — Detailed Notes

Sexual Reproduction — External Fertilization

In external fertilization, both sperm and egg are released into water, where fusion occurs. This exposes gametes to predation and environmental hazards, so organisms produce vast numbers of eggs to compensate (e.g., a single cod can release millions of eggs per spawning).

Key Term

Induced Breeding (Hypophysation): In aquaculture, hormones (pituitary extract or synthetic hormones like Ovaprim) are injected into brood fish to stimulate spawning on demand. This is a controlled form of external fertilization used in catfish, carp, and rohu farming. India is the world's 2nd largest aquaculture producer (after China); inland fisheries contribute ~77% of India's fish production (DAHD data).

Sexual Reproduction — Internal Fertilization

Internal fertilization, where sperm is deposited inside the female's body, evolved to suit terrestrial environments where water is not available as a medium. Fewer offspring are produced, but survival rates are higher due to greater parental investment.

  • Reptiles: Internal fertilization; lay leathery eggs (oviparous); e.g., sea turtles — critical for wildlife conservation
  • Birds: Internal fertilization; hard-shelled eggs; incubation provides warmth
  • Mammals: Internal fertilization; most are viviparous with placental development
UPSC Connect

UPSC GS3 — Sea Turtle Conservation: All five sea turtle species found in Indian waters — Olive Ridley, Green, Hawksbill, Loggerhead, and Leatherback — are listed under Schedule I of the Wildlife Protection Act 1972 and CITES Appendix I. Olive Ridley mass nesting (Arribada) at Gahirmatha (Odisha) and Rushikulya is a flagship conservation event. Their oviparous reproduction (nesting on beaches) makes them vulnerable to beach erosion, light pollution, and poaching. The TED (Turtle Excluder Device) mandate for trawlers in Odisha waters reduces accidental bycatch.

Asexual Reproduction

Asexual reproduction produces genetically identical offspring (clones) from a single parent. Key types tested in UPSC:

  • Budding (Hydra): A small outgrowth (bud) develops on the parent's body, grows, and eventually detaches to become an independent organism
  • Binary Fission (Amoeba): The parent cell divides into two equal daughter cells, each becoming a complete individual
  • Regeneration (Planaria, Starfish): A fragment of the organism can regenerate into a complete individual — distinct from simple healing
Explainer

Why regeneration matters beyond the classroom: Starfish regeneration is the scientific basis for studying stem cell biology. Planaria (flatworm) is a model organism in regenerative medicine research — it can regrow its entire body including the brain. This connects to GS3 biotechnology: stem cell research, organ regeneration, and India's regulatory framework for stem cell therapies (ICMR guidelines).

Cloning — Science, Ethics, and India

Somatic Cell Nuclear Transfer (SCNT): The nucleus (containing DNA) from a somatic (body) cell of the animal to be cloned is transferred into an enucleated egg cell. The egg is then stimulated to divide and implanted into a surrogate mother.

UPSC Connect

UPSC GS3 — Cloning Policy:

  • Reproductive cloning (creating a cloned human being) is banned worldwide under various national laws and condemned by the UN Declaration on Human Cloning (2005).
  • Therapeutic cloning (creating cloned embryos to harvest stem cells for treating diseases) remains ethically debated — legal in the UK (under strict regulation) and some other countries; not permitted in India under ICMR guidelines.
  • Animal cloning for livestock: Legitimate use — NDRI, Karnal cloned buffalo Garima (2009) and Garima-II (2010) to multiply high-yielding cattle genetics rapidly. NDRI is under ICAR (Indian Council of Agricultural Research).
  • Extinction reversal (de-extinction): Proposals to clone extinct species (e.g., woolly mammoth, gastric-brooding frog) using ancient DNA — scientifically feasible in theory but raises deep ecological ethics questions about reintroduction into changed habitats.

IVF and Assisted Reproductive Technology (ART)

In Vitro Fertilisation (IVF): Eggs are retrieved from the female, fertilized with sperm in a laboratory dish, and the resulting embryo is transferred into the uterus.

UPSC Connect

UPSC GS3/GS2 — ART Regulation Act 2021: India enacted the Assisted Reproductive Technology (Regulation) Act, 2021 to regulate IVF clinics and banks (storing sperm, eggs, embryos). Key provisions:

  • National and State ART Boards to register and regulate clinics
  • Age limits: Women 21–50, men 21–55 years for commissioning ART
  • Limits on number of donated eggs per donor (maximum 7 oocytes)
  • Prohibition of sex selection (under PCPNDT Act 1994 as well)
  • Pre-implantation genetic testing (PGT) allowed for medical reasons only

Surrogacy (Regulation) Act, 2021:

  • Bans commercial surrogacy (paying a surrogate beyond medical expenses)
  • Allows altruistic surrogacy only — surrogate must be a willing close relative (married, with own child, aged 25–35)
  • Intended couple must be Indian citizens; widows and divorcees also permitted since 2023 amendment
  • National Surrogacy Board and State Surrogacy Boards for regulation

Reproductive Technologies for Wildlife Conservation

UPSC Connect

UPSC GS3 — Ex-situ Conservation & ART: Reproductive technologies are increasingly used for ex-situ conservation of endangered species:

  • Cryopreservation: Freezing sperm, eggs, embryos, and somatic cells of endangered animals for future use — India is developing a National Cryogenic Wildlife Sperm Bank at CCMB (Centre for Cellular and Molecular Biology), Hyderabad
  • IVF for endangered species: Used in cheetah (Acinonyx jubatus) breeding programs, giant panda, and northern white rhino (only 2 left in the world — ART is the only hope)
  • Project Hangul (Kashmir Stag): Assisted reproduction research for Cervus hanglu hanglu — critically endangered; population ~260 in Dachigam National Park
  • Studbooks: Zoo-maintained genetic records used to manage breeding programs and prevent inbreeding (managed by CAZS — Central Zoo Authority of India)

Exam Strategy

Prelims traps:

  • Dolly was cloned at Roslin Institute, Scotland — not Edinburgh University (it was affiliated but distinct)
  • India's first cloned animal was a buffalo (Garima, 2009) — not a cow or sheep
  • India's first IVF baby Durga was born in 1978 — same year as Louise Brown (UK); Dr. Subhas Mukherjee's work was initially not recognized by the Indian medical establishment
  • Platypus is a mammal (monotreme) that lays eggs — oviparous exception among mammals
  • ART Regulation Act 2021 and Surrogacy Regulation Act 2021 are separate laws — common confusion in MCQs
  • Commercial surrogacy is banned in India under the 2021 Act; only altruistic surrogacy is permitted
  • NDRI (National Dairy Research Institute) is located in Karnal, Haryana — under ICAR

Previous Year Questions

Prelims:

  1. Which of the following statements about Dolly, the cloned sheep, is correct?
    (a) Dolly was the first animal cloned using embryonic stem cells
    (b) Dolly was cloned using a technique called Binary Fission
    (c) Dolly was cloned using Somatic Cell Nuclear Transfer (SCNT) at the Roslin Institute
    (d) Dolly was cloned by scientists at NDRI, Karnal

  2. With reference to India's Assisted Reproductive Technology (Regulation) Act 2021, consider the following statements:

    1. It regulates IVF clinics and gamete banks across India
    2. It permits commercial surrogacy under defined conditions
    3. It bans sex selection at the pre-implantation stage
      Which of the above statements are correct?
      (a) 1 and 2 only
      (b) 1 and 3 only
      (c) 2 and 3 only
      (d) 1, 2 and 3

Mains:

  1. What is Somatic Cell Nuclear Transfer (SCNT)? Discuss the ethical concerns surrounding human reproductive cloning and the Indian regulatory framework for Assisted Reproductive Technologies. (CSE Mains 2022, GS Paper 3, 15 marks)

  2. Discuss the role of assisted reproductive technology (ART) in ex-situ conservation of endangered species in India. (CSE Mains 2019, GS Paper 3, 10 marks)