NEET MCQs Inheritance and Variation [Free PDF Download]

Class 12 Biology & NEET Preparation

NEET MCQs Inheritance and Variation

Downloading the NEET MCQs Inheritance and Variation practice module equips medical aspirants and Class 12 students with comprehensive practice sets, Mendelian laws, gene interactions, pedigree charts, and solved past-year questions. Published by MathScience Academy, this PDF covers Monohybrid and Dihybrid crosses, Incomplete Dominance, Codominance, Multiple Allelism, Linkage and Recombination, Sex Determination, and Genetic Disorders.

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NEET MCQs Inheritance and Variation Overview

In NEET Biology, classical genetics carries immense weightage. Practicing NEET MCQs Inheritance and Variation builds speed and accuracy for conceptual numericals on test crosses, gene mapping distances, pedigree analysis, ABO blood grouping, and chromosomal aberrations.

If you are organizing your complete science study plan, explore our central library for Free Science Study Materials or examine high school mathematics directories like Class 10 Coordinate Geometry Olympiad.

What’s Included in NEET MCQs Inheritance and Variation

Resource ModuleKey Topics CoveredFormatAction
Mendelian Genetics & RatiosLaw of Dominance, Segregation, Independent Assortment, Monohybrid and Dihybrid Crosses.Free PDF View / DownloadDownload PDF
Non-Mendelian Inheritance & LinkageIncomplete Dominance, Codominance, Multiple Alleles, Pleiotropy, Polygenic Traits, Morgan’s Linkage.Included in PDFDownload PDF
Genetic Disorders & Pedigree MCQsMendelian disorders (Hemophilia, Sickle-cell, Thalassemia) and Chromosomal disorders (Down, Klinefelter, Turner).Included in PDFDownload PDF

Important Genetic Laws, Ratios & Crosses Reference Table

Essential Mendelian and Non-Mendelian phenotypic/genotypic ratios covered in NEET MCQs Inheritance and Variation for quick revision:

Genetic Cross / InteractionPhenotypic Ratio ($F_2$)Genotypic Ratio ($F_2$)Classic Example Organism / Trait
Monohybrid Cross$3 : 1$$1 : 2 : 1$Garden Pea Tall vs. Dwarf ($TT \times tt$)
Dihybrid Cross$9 : 3 : 3 : 1$$1:2:2:4:1:2:1:2:1$Seed Shape & Seed Color ($RRYY \times rryy$)
Incomplete Dominance$1 : 2 : 1$$1 : 2 : 1$Snapdragon (*Antirrhinum majus*) Flower Color
Codominance$1 : 2 : 1$$1 : 2 : 1$Human ABO Blood Group ($I^A, I^B, i$)
Test Cross (Monohybrid)$1 : 1$$1 : 1$Unknown Dominant Genotype $\times$ Recessive Parent ($Tt \times tt$)
Test Cross (Dihybrid)$1 : 1 : 1 : 1$$1 : 1 : 1 : 1$Heterozygous Dihybrid $\times$ Double Recessive ($AaBb \times aabb$)

NEET MCQs Inheritance and Variation Chapter Breakdown

Module 1: Mendelian Laws & Deviations

Mastering classical Mendelian inheritance and extended allelic interactions:

  • Mendel’s Principles: Law of Dominance, Law of Segregation (Purity of Gametes), and Law of Independent Assortment.
  • Deviations from Mendelism: Incomplete Dominance (*Mirabilis jalapa*), Codominance ($I^A I^B$ blood group), Multiple Allelism, and Pleiotropy (Phenylketonuria).
  • Polygenic Inheritance: Continuous variation controlled by multiple additive genes (e.g., Human skin color, height).

Module 2: Chromosomal Theory, Linkage & Sex Determination

Understanding physical chromosome behavior, recombination frequency, and sex-linked traits:

  • Chromosomal Theory of Inheritance: Proposed by Sutton and Boveri; validated experimentally by T.H. Morgan using *Drosophila melanogaster*.
  • Linkage & Recombination: Tightly linked genes stay together ($F_2$ parental types > recombinants); Recombination frequency $1\% = 1 \text{ centimorgan (cM)}$.
  • Sex Determination Systems: $XX-XY$ type (Humans, *Drosophila*), $XX-XO$ type (Grasshoppers), $ZZ-ZW$ type (Birds), and Honeybee Haplodiploidy.

Module 3: Pedigree Analysis & Genetic Disorders

Analyzing inheritance modes in human family trees and chromosome structural/numerical defects:

  • Pedigree Analysis Tricks: Autosomal Dominant (Myotonic dystrophy), Autosomal Recessive (Sickle-cell anemia, Phenylketonuria), X-linked Recessive (Hemophilia, Color blindness).
  • Mendelian Disorders: Hemophilia (Royal disease), Sickle-cell anemia ($\text{GAG} \to \text{GUG}$ mutation in $\beta$-globin chain), and Thalassemia.
  • Chromosomal Disorders: Aneuploidy due to non-disjunction—Down Syndrome ($21^\text{st}$ trisomy), Klinefelter Syndrome ($47, XXY$), Turner Syndrome ($45, XO$).

Sample Solved Genetics Problem

Here is an example problem from the NEET MCQs Inheritance and Variation practice set:

Problem: ABO Blood Group Inheritance Probability

Question: A man with Blood Group A (whose mother had Blood Group O) marries a woman with Blood Group B (whose father had Blood Group O). What are the possible blood groups and their probabilities in their children?

Step-by-Step Solution:

  1. Determine Parental Genotypes:
    Since the man has Blood Group A and his mother was O ($ii$), he must carry the recessive $i$ allele. Genotype = $I^A i$.
    Since the woman has Blood Group B and her father was O ($ii$), she must carry the recessive $i$ allele. Genotype = $I^B i$.
  2. Construct the Cross ($I^A i \times I^B i$):
    Gametes from Man: $I^A$ and $i$
    Gametes from Woman: $I^B$ and $i$
  3. Punnett Square Offspring Genotypes:
    • $I^A \times I^B \to I^A I^B$ (Blood Group AB) — $25\%$
    • $I^A \times i \to I^A i$ (Blood Group A) — $25\%$
    • $I^B \times i \to I^B i$ (Blood Group B) — $25\%$
    • $i \times i \to ii$ (Blood Group O) — $25\%$
  4. Conclusion:
    All four blood groups (AB, A, B, and O) are equally likely in their children with a ratio of $1 : 1 : 1 : 1$ ($25\%$ probability each).

How to Study NEET MCQs Inheritance and Variation

  1. Master Test Cross Calculations: Learn to identify unknown parental genotypes by analyzing offspring phenotypic ratios.
  2. Memorize Pedigree Symbols & Rules: Practice identifying Autosomal vs. Sex-linked and Dominant vs. Recessive inheritance patterns instantly.
  3. Understand Gene Mapping: Remember that $1\%$ recombination frequency equals $1 \text{ Map Unit (mu) / cM}$; map distances are additive.
  4. Solve Objective NEET Questions: Practice multi-statement and match-the-column MCQs directly from NCERT textbook lines.

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Frequently Asked Questions (FAQs)

How do I access the NEET MCQs Inheritance and Variation PDF?

You can directly view and download the PDF by clicking the download buttons above or via this link: NEET MCQs Inheritance and Variation PDF Download.

Is this material aligned with the CBSE Class 12 & NEET Biology syllabus?

Yes. It thoroughly covers Class 12 NCERT Principles of Inheritance and Variation along with competitive numerical practice questions, Mendelian ratios, and pedigree analysis diagrams for NEET.

What is the difference between incomplete dominance and codominance?

In incomplete dominance, the heterozygous phenotype is an intermediate blend between both homozygous traits (e.g., Red + White = Pink in Snapdragon). In codominance, both alleles express themselves fully together without blending (e.g., $I^A I^B$ blood group expressing both A and B antigens).

NEET MCQs Inheritance and Variation

Class-wise Solutions

Class 12:

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