Principles of Inheritance and Variation

In the hexaploid wheat, the haploid (n) and basic (x) numbers of chromosomes are:

1. n = 21 and x = 14
2. n = 21 and x = 21
3. n = 7 and x = 21
4. n = 21 and x = 7

A common test to find the genotype of a hybrid is by:-

1. Crossing of one F1 progeny with recessive parent
2. Crossing of one F2 progeny with female parent
3. Crossing of one F2 progeny with male parent
4. Studying the sexual behaviour of F1 progenies

Both sickle cell anemia and Huntington's chorea are-

1. Congenital disorders
2. Bacteria-related diseases
3. Virus-related diseases
4. Pollutant-induced disorders

Test cross involves-

1. Crossing between two F1 hybrids
2. Crossing the F1 hybrid with a double recessive genotype
3. Crossing between two genotypes with recessive trait
4. Crossing between two genotypes with dominant trait

If a colour blind woman marries a normal visioned man, their sons will be

1. All normal visioned
2. Three-fourths colourblind and one-fourth normal
3. One-half colourblind and one-half normal
4. All colourblind

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