Principles of Inheritance
Monohybrid cross
Ek trait ko do generations tak follow karo, to ek clear pattern dikhta hai: teen dominant look wale, ek recessive look wala.
Do pure parents se shuru karo, tall (TT) aur short (tt). F₁ saare Tt hote hain, aur saare tall. Inhe self-cross karo, to F₂ aate hain 3 : 1, teen tall aur ek short.
Short plants wapas aate hain kyunki hidden t copy phir se pair bana sakti hai. 3 : 1 look ke peeche ek 1 : 2 : 1 genotype ratio hota hai: ek TT, do Tt, ek tt.
Yahaan students galti karte hain
Bahut se students F₂ ke liye ‘3 : 1’ likh kar ruk jaate hain. Par exam aksar neeche wala genotype ratio maangta hai: 1 : 2 : 1. Teen tall me se do carriers (Tt) hain, pure nahi. Look aur genotype do alag sawaal hain.
Yaad rakho
3 : 1 wo hai jo dikhta hai. 1 : 2 : 1 wo hai jo asal me hai.
Exam me kaise kaam aata hai: F₂ ka 3 : 1 sabse zyada poocha jaane wala Mendelian result hai. Look ratio aur neeche ka 1 : 2 : 1 dono yaad rakho.
Ek quick check
Monohybrid cross me F₂ look ratio 3 : 1 hai. Iske peeche genotype ratio hai:
- A3 : 1
- B1 : 2 : 1
- C9 : 3 : 3 : 1
- D1 : 1