Principles of Inheritance and Variation

Cri-du-chat syndrome in humans is caused by the-

1. Loss of half of the long arm of chromosome 5
2. Loss of half of the short arm of chromosome 5
3. Trisomy of 21st chromosome
4. Fertilization of an XX egg by a normal Y-bearing sperm

Sickle cell anaemia has not been eliminated from the African population because-

1. It is not a fatal disease
2. It is controlled by dominant genes
3. It is controlled by recessive genes
4. It provides immunity against malaria

In Mendel's experiments with garden pea, round seed shape (RR) was dominant over wrinkled seeds (rr), yellow cotyledon (YY) was dominant over green cotyledon (yy). What are the expected phenotypes in the F2 generation of the cross RRYY × rryy?

1. Round seeds with yellow cotyledons, and wrinkled seeds with yellow cotyledons
2. Only wrinkled seeds with green cotyledons
3. Only wrinkled seeds with yellow cotyledons
4. Only round seeds with green cotyledons

How many different kinds of gametes will be produced by a plant having the genotype AABbCC?

1. Two
2. Nine
3. Four
4. Three

Phenotype of an organism is the result of-

1. Environmental changes and sexual dimorphism
2. Cytoplasmic effects and nutrition
3. Genotype and environment interactions
4. Mutations and linkages

Which one of the following is an example of polygenic inheritance?

1. Skin colour in humans
2. Pod shape in garden pea
3. Production of male honey bee
4. Flower colour in Mirabilis jalapa

In order to find out the different types of gametes produced by a pea plant having the genotype AaBb, it should be crossed to a plant with the genotype -

1. aaBB
2. aabb
3. AaBb
4. AABB

G-6-P dehydrogenase deficiency is associated with haemolysis of -

1. RBCs
2. Lymphocytes
3. Platelets
4. Leucocytes

A man and a woman, who do not show any apparent signs of a certain inherited disease, have seven children (2 daughters and 5 sons). Three of the sons suffer from the given disease but none of the daughters are affected. Which of the following mode of inheritance do you suggest for this disease?

1. Autosomal dominant
2. Sex-linked recessive
3. Sex-linked dominant
4. Sex-limited recessive

A woman with 47 chromosomes due to three copies of chromosome 21 is characterized by -

1. Superfemaleness
2. Turner's syndrome
3. Triploidy
4. Down's syndrome