Class 12 · Principles of Inheritance and Variation

Law of Segregation & Allele Behavior — NEET Biology

🔥 Predicted for NEET 2027
📖 NCERT Source

This law is based on the fact that the alleles do not show any blending and that both the characters are recovered as such in the F₂ generation though one of these is not seen at the F₁ stage. Though the parents contain two alleles during gamete formation, the factors or alleles of a pair segregate from each other such that a gamete receives only one of the two factors. Of course, a homozygous parent produces all gametes that are similar while a heterozygous one produces two kinds of gametes each having one allele with equal proportion.

NCERT Biology · Class 12 · Chapter 4 · Paragraph 34
Why This May Be Tested in NEET 2027

Adjacent to a frequently-asked paragraph in the same chapter.

Practice This Concept
QuestionPredicted for NEET 2027

Match the Column Match phenomena to their precise features. Column I A. Law of Segregation B. Incomplete dominance C. Codominance (ABO) D. Test cross E. Phenotype vs Genotype Column II (i) “F₁ was pink… phenotype ratios… changed from 3:1” (ii) “Alleles… segregate… a gamete receives only one” (iii) “IA and IB… both express their own types of sugars” (iv) “Cross… dominant phenotype… with the recessive parent” (v) “TT/tt = genotype; tall/dwarf = phenotype”

📖 Solution & NCERT Explanation
View solution & NCERT explanation

Correct answer: A A–(ii), B–(i), C–(iii), D–(iv), E–(v)

Law of segregation = allele separation; incomplete dominance = pink; codominance = IA, IB both expressed; test cross uses recessive parent; phenotype vs genotype distinction.

❓ Frequently Asked Questions
What does NCERT say about This law based on?
This law is based on the fact that the alleles do not show any blending and that both the characters are recovered as such in the F₂ generation though one of these is not seen at the F₁ stage. Though the parents contain two alleles during gamete formation, the factors or alleles of a pair segregate from each other such that a gamete receives only one of the two factors.
Has this concept appeared in NEET?
High probability for NEET 2027. Adjacent to a frequently-asked paragraph in the same chapter.
Which chapter is this from?
Principles of Inheritance and Variation, Class 12 NCERT Biology.

Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.

176/180
of the ReNEET 2026 paper (all subjects) was already in the MedicNEET question bank

MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.

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