Describe cloning (reproductive and therapeutic)
6.3.9· Biology › Biotechnology Applications
Cloning KYA hai?
Kyunki koi meiosis nahi hota aur do gametes ke beech koi fertilisation nahi hoti, offspring ka DNA ek single donor se aata hai. Isliye copy genetically same hoti hai (mutations aur mitochondrial DNA ko chhodkar, jo neeche discuss ki gayi hai).
Yeh kaam karta hi kyun hai? Aapke body ki har somatic cell mein poora genome hota hai (yeh genomic equivalence hai). Ek skin cell sirf skin genes use karti hai, lekin usme poore animal ke genes contained hote hain. Egg cytoplasm mein aisi factors hoti hain jo nucleus ko "reset" karti hain — genes ko wapas switch on karti hain taaki pura body plan dobara build ho sake.
Dono types mein FARQ kya hai
Dono usi tarah shuru hote hain (SCNT → early embryo). Yeh blastocyst stage par alag ho jaate hain:
| Feature | Reproductive cloning | Therapeutic cloning |
|---|---|---|
| Goal | Poori living organism produce karna | Embryonic stem cells / tissue produce karna |
| Embryo ka fate | Surrogate uterus mein implant hota hai | In vitro grow hota hai; inner cell mass harvest hoti hai |
| End product | Ek naya individual (jaise Dolly) | Stem cells → patient ke liye replacement tissue |
| Birth tak jaata hai? | Haan | Nahi (embryo implant nahi hota) |
Reproductive cloning — steps ko scratch se samajhna
Aao protocol ko build karte hain — reasoning se, na ki ratta maar ke.
- Hum donor animal D ki genetic copy chahte hain. Toh DNA sirf D se aana chahiye. → D se ek somatic cell lo (uske nucleus mein D ka poora genome hai).
- Ek nucleus akela develop nahi ho sakta. Ise reprogram karne ke liye egg cytoplasm chahiye + machinery supply karni padti hai. → Usi species ki kisi doosri female se ek egg lo.
- Egg ke apne genes hatane padenge, warna offspring ek mix hogi. → Egg ko enucleate karo.
- Dono ko combine karo. D ka nucleus enucleated egg mein insert karo (micro-injection ya electric pulse se fusion). Ab egg mein D ka diploid genome hai.
- Division trigger karo. Ek electric/chemical shock fertilisation ko mimic karta hai → egg mitosis shuru karta hai → embryo (blastocyst) banta hai.
- Poora animal ugao. Embryo ko surrogate mother ke uterus mein implant karo → pregnancy → D ke clone ka birth.
Therapeutic cloning — steps ko samajhna
Pehle 5 steps upar wale jaisi hi hain (SCNT → blastocyst). Phir:
- Implant mat karo. Balki blastocyst ko in vitro grow karo.
- Inner cell mass harvest karo → yeh embryonic stem (ES) cells hain, jo pluripotent hoti hain (kisi bhi body cell type mein ban sakti hain).
- ES cells ko differentiate karo (specific growth factors use karke) us tissue mein jo patient ko chahiye — jaise insulin-producing pancreatic cells, neurons, cardiac muscle.
- Patient mein transplant karo.
Clone ek perfect copy kyun nahi hota
Recall Feynman: ek 12-saal ke bachche ko explain karo
Socho ki ek sheep ki har cell mein poori sheep banane ki "recipe book" hai, lekin skin cells sirf "skin chapter" pakaati hain. Clone karne ke liye, hum woh recipe book (nucleus) skin cell se nikaalta hain aur ek khali egg mein daalte hain — ek aisa egg jise hum ne hollow out kar diya. Egg magical hai: woh kehta hai "page one se shuru karo!" aur poori recipe reboot ho jaati hai. Agar hum phir is rebooted egg ko ek mummy sheep ke pet mein daalen, toh yeh ek nayi sheep ban jaati hai jo recipe ke owner jaisi dikhti hai — yeh hai reproductive cloning (jaise Dolly). Lekin agar hum cells ki us choti si ball ko dish mein rakhen aur sirf ek nayi tissue ka patch ugaane ke liye use karein (jaise ek beemar insaan ke liye fresh insulin cells), toh yeh hai therapeutic cloning — koi baby nahi, sirf ek repair part jo patient ki body fight nahi karegi, kyunki yeh unki apni recipe se banaya gaya hai.
Active-recall flashcards
Clone kya hota hai?
SCNT ka full form aur matlab kya hai?
Nuclear transfer se pehle egg ko enucleate kyun karna padta hai?
Somatic cells ki kaunsi property cloning ko possible banati hai?
Reproductive aur therapeutic cloning kis stage par alag hote hain?
Reproductive cloning mein embryo ka fate kya hota hai?
Therapeutic cloning mein embryo ka fate kya hota hai?
Dolly kis sheep ki clone thi, aur proof kya tha?
Therapeutic cloning se bani tissue patient reject kyun nahi karta?
Clone 100% identical kyun NAHI hota?
SCNT aur IVF mein kya farq hai?
ES cells kya hain aur useful kyun hain?
Connections
- Stem Cells and Pluripotency — therapeutic cloning mein tissues ka source
- Totipotency and Genomic Equivalence — woh principle jo ek somatic nucleus ko poori organism rebuild karne deta hai
- Mitochondrial DNA Inheritance — kyun clones perfect copies nahi hote
- Immune Rejection and MHC/HLA — kyun patient-derived tissue rejection se bachti hai
- IVF and Assisted Reproduction — contrast: sexual vs asexual
- Recombinant DNA and Molecular Cloning — genes ki "cloning" vs poori organisms
- Ethical Issues in Biotechnology — embryo use par debate