controls multiple traits in an individual.

is a gene evolved during Pliocene.

controls a trait only in combination with another gene.

is expressed in only primitive plants.

MEDIUM

Earn 100

Assertion: ABO blood group system is a good example of pleiotropic genes.
Reason: In ABO blood group system, when I^A and I^B alleles are present together, both express themselves.

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Important Questions on Principles of Inheritance and Variation

EASY

Biology>Genetics and Evolution>Principles of Inheritance and Variation>Inheritance of One Gene

A gene showing codominance has

EASY

Biology>Genetics and Evolution>Principles of Inheritance and Variation>Inheritance of One Gene

Which one of the following genetic phenomena is represented by the blood group AB?

MEDIUM

Biology>Genetics and Evolution>Principles of Inheritance and Variation>Inheritance of One Gene

$ABO$ blood type in man is an example of

1. Pleiotropy

2. Incomplete dominance

3. Co-dominance

4. Multiple allelism

Select the code for the correct answer from the options given below:

MEDIUM

Biology>Genetics and Evolution>Principles of Inheritance and Variation>Inheritance of One Gene

Match the terms in Column-I with their description in Column-II and choose the correct option:

Column – I	Column – II
(a) Dominance	(i) Many genes govern a single character
(b) Codominance	(ii) In a heterozygous organism, only one allele expresses itself
(c) Pleiotropy	(iii) In a heterozygous organism, both alleles express themselves fully
(d) Polygenic inheritance	(iv) A single gene influences many characters

MEDIUM

Biology>Genetics and Evolution>Principles of Inheritance and Variation>Inheritance of One Gene

In human beings, brown eye (B) is dominant over blue eye (b). A brown-eyed couple has a blue-eyed child. What are the possible genotypes of the couple?

EASY

Biology>Genetics and Evolution>Principles of Inheritance and Variation>Inheritance of One Gene

Which one of the following pairs of genotype and phenotype ratios will be obtained in

F_{2}

generation for Snapdragon plants exhibiting incomplete dominance for red and white flower color traits?

MEDIUM

Biology>Genetics and Evolution>Principles of Inheritance and Variation>Inheritance of One Gene

If the gene pool of the locus X in the human genome is 4, then what would be the highest possible number of genotypes in a large population?

MEDIUM

Biology>Genetics and Evolution>Principles of Inheritance and Variation>Inheritance of One Gene

The genotypes of a Husband and Wife are

I^{A} I^{B}

and

I^{A} i

.
Among the blood types of their children, how many different genotypes and phenotypes are possible?

EASY

Biology>Genetics and Evolution>Principles of Inheritance and Variation>Inheritance of One Gene

A man with blood group A marries a woman having blood group. The maximum possible blood groups among their progenies are

EASY

Biology>Genetics and Evolution>Principles of Inheritance and Variation>Inheritance of One Gene

In a cross between true-breeding (homozygous) red-flowered and true-breeding (homozygous) white flowered plants, the

F_{1}

progeny was pink. The phenotypic and genotypic ratios in

F_{2}

progency were

1 : 2 : 1

. This is because of:

EASY

Biology>Genetics and Evolution>Principles of Inheritance and Variation>Inheritance of One Gene

A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the

F_{1}

plants were selfed the resulting genotypes were in the ratio

MEDIUM

Biology>Genetics and Evolution>Principles of Inheritance and Variation>Inheritance of One Gene

In Antirrhinum (Snapdragon), a red flower was crossed with a white flower and in F₁ generation, pink flowers were obtained. When pink flowers were selfed, the F₂ generation showed white, red and pink flowers. Choose the incorrect statement from the following.

EASY

Biology>Genetics and Evolution>Principles of Inheritance and Variation>Inheritance of One Gene

The production of gametes by the parents, formation of zygotes, the