Genetics - NEET Previous Year Questions

Team eSaral

30th May 2026

3 min read

Summary

<p>Genetics is one of the highest-weightage NEET Biology chapters, contributing 5–7 questions annually with a strong focus on Mendelian inheritance, dihybrid crosses, sex-linked inheritance, chromosomal disorders, and pedigree analysis, while this page provides previous year questions, key concepts, and preparation strategies to master recurring NEET patterns.</p>

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Why Genetics Is a Must-Master Chapter for NEET Biology

Parameter	Details
NCERT Chapter	Principles of Inheritance and Variation (Class 12, Chapter 5)
Average questions per NEET paper	5–7 questions
Marks weightage	20–28 marks per year
Difficulty level	Moderate — conceptual + problem-solving
Most tested subtopics	Mendel's laws, dihybrid cross ratios, sex determination, sex-linked inheritance, chromosomal disorders
Closely related chapter	Molecular Basis of Inheritance (Class 12, Chapter 6) — 3–5 more questions

💡 Expert Tip by eSaral Academic Team, IIT Bombay Faculty: "Genetics is one of the few NEET Biology chapters where you can predict the exact type of question before you see it. NEET has tested dihybrid cross ratios, sex-linked inheritance numerical problems, and ABO blood group inheritance almost every year since 2013. Master these three question types and you have 8–10 marks locked before the exam begins."

Genetics NEET Previous Year Questions with Solutions

High-Frequency Subtopics in Genetics NEET PYQs

Based on analysis of NEET papers from 2013 to 2025:

Subtopic	Frequency	What NEET Tests
Mendel's Laws (Dominance, Segregation, Independent Assortment)	Very High	Ratio prediction, law identification
Monohybrid and Dihybrid cross ratios	Very High	F1/F2 ratio calculation, phenotype/genotype counts
Incomplete dominance and codominance	High	ABO blood groups, sickle cell anaemia
Sex determination mechanisms	High	XX-XY, ZW-ZZ, XO systems
Sex-linked (X-linked) inheritance	High	Colour blindness, haemophilia problems
Chromosomal disorders	High	Down's, Turner's, Klinefelter's syndrome
Linkage and crossing over	Medium	Morgan's experiments, recombination frequency
Pedigree analysis	Medium	Autosomal dominant/recessive, X-linked patterns
Mutation types	Medium	Point mutation, frameshift, chromosomal
Polygenic inheritance	Low-Medium	Skin colour, height inheritance

Key Concepts Summary for Quick Revision

Concept	Key Fact
Monohybrid F2 ratio	3:1 (phenotypic); 1:2:1 (genotypic)
Dihybrid F2 ratio	9:3:3:1
Test cross (monohybrid heterozygote)	1:1
Test cross (dihybrid heterozygote, unlinked)	1:1:1:1
Incomplete dominance F2	1:2:1 (phenotypic = genotypic)
Codominance example	ABO blood groups (I^A I^B = AB)
Colour blindness / Haemophilia	X-linked recessive
Sex determination (humans)	XX = female; XY = male
Down's Syndrome	Trisomy 21 (47 chromosomes)
Turner's Syndrome	45,XO (monosomy X)
Klinefelter's Syndrome	47, XXY
Linkage	Genes on the same chromosome; violates independent assortment
Recombination frequency	Distance between linked genes

How to Prepare Genetics for NEET

Step 1: Master Mendel's Laws with Punnett Squares

Do not move to complex Genetics topics until monohybrid and dihybrid cross Punnett squares are completely automatic. Practise 20–30 cross problems — including test crosses and back crosses — until ratios come to you without drawing the full grid.

Step 2: Learn All Chromosomal Disorders as a Table

Down's (Trisomy 21), Turner's (45,XO), Klinefelter's (47,XXY), Patau's (Trisomy 13), Edward's (Trisomy 18) — memorise chromosome composition, phenotype, and distinguishing features for each. NEET tests these as 1-mark identification questions.

Step 3: Solve Sex-Linked Inheritance Problems Methodically

Always write genotypes using full notation (X^H, X^h, Y). Never assume — always derive the answer from the cross. NEET sex-linked problems are straightforward if you use proper notation; they become error-prone if you try to solve them in your head.

Step 4: Work Through All NEET PYQs from This Chapter

Pattern recognition from past papers is irreplaceable for Genetics. Visit eSaral's NEET previous year questions and solve all Genetics PYQs year by year. After 5–6 years of papers, NEET's preferred question formats become very familiar.

Step 5: Connect Genetics to the Molecular Basis of Inheritance

NEET treats these as two chapters but the questions overlap significantly. DNA replication, transcription, translation, and mutation concepts directly connect to Genetics. Prepare both chapters together for maximum efficiency.

Frequently Asked Questions

How many questions come from Genetics in NEET every year?

Genetics (Principles of Inheritance and Variation) contributes 5–7 questions per NEET paper, worth 20–28 marks. When combined with the related Molecular Basis of Inheritance chapter, the total reaches 8–12 questions. It is consistently one of the most heavily tested Biology chapters in NEET. Mendel's laws, sex-linked inheritance, and chromosomal disorders appear almost every year.

What is the most important topic in Genetics for NEET?

Mendelian genetics — specifically dihybrid cross ratios and test cross interpretation — is the single most important Genetics topic for NEET. Sex-linked inheritance (colour blindness and haemophilia numerical problems) is a close second. Together, these two areas account for 3–4 questions per year. Chromosomal disorders (Down's, Turner's, Klinefelter's) are also consistently tested and can be prepared with a simple memorisation table.

What is the difference between incomplete dominance and codominance in NEET?

In incomplete dominance, the heterozygote shows a phenotype intermediate between the two homozygotes — neither allele fully dominates (e.g., pink flowers from red × white). In codominance, both alleles are fully expressed simultaneously in the heterozygote — neither suppresses the other (e.g., ABO blood group AB from I^A × I^B). NEET distinguishes these in questions about ABO blood groups and flower colour inheritance.

What are the chromosomal compositions of major genetic disorders tested in NEET?

Down's Syndrome has trisomy 21 (47 chromosomes). Turner's Syndrome has monosomy X (45,XO — female phenotype, infertile). Klinefelter's Syndrome has 47,XXY (male phenotype, infertile, gynaecomastia). Patau's Syndrome has trisomy 13 (47 chromosomes, severe defects). Edward's Syndrome has trisomy 18 (47 chromosomes). All result from non-disjunction during meiosis.

Where can I find all NEET Biology previous year questions chapter wise?

SL Arora Physics Class 12 index — complete chapter list for Volume 1 & 2, mapped to NCERT solutions for board, JEE Main, and NEET preparation.

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