Principles of Inheritance and Variation

A cross in which an organism showing a dominant phenotype is crossed with the recessive parent in order to know its genotype is called -

1. Dihybrid cross
2. Back cross
3. Monohybrid cross
4. Test cross

In Antirrhinum two plants with pink flowers were hybridized. The F1 plants produced red, pink and white flowers in the proportion of 1 red, 2 pink and 1 white. What could be the genotype of the two plants used for hybridization? Red flower colour is determined by RR, and White by rr genes -

1. rrrr
2. rr
3. Rr
4. RR

Which one of the following symbols and its representation, used in human pedigree analysis is correct –

1. [figure] = mating between relatives
2. [figure] = unaffected female
3. [figure] = unaffected male
4. [figure] = male affected

ABO blood groups in humans are controlled by the gene I. It has three alleles – IA, IB and i. Since there are three different alleles, six different genotypes are possible. How many phenotypes can occur –

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

Select the correct statement from the ones given below with respect to dihybrid cross –

1. Genes far apart on the same chromosome show very few recombinations
2. Tightly linked genes on the same chromosome show very few recombinations
3. Tightly linked genes on the same chromosome show higher recombinations
4. Genes loosely linked on the same chromosome show similar recombinations as the tightly linked ones

The genotype of a plant showing the dominant phenotype can be determined by –

1. Pedigree analysis
2. Back cross
3. Test cross
4. Dihybrid cross

Which one of the following cannot be explained on the basis of Mendel's Law of Dominance?

1. Out of one pair of factors one is dominant, and the other recessive
2. Alleles do not show any blending and both the characters recover as such in F2 generation
3. The discrete unit controlling a particular character is called a factor
4. Factors occur in pairs

Select the incorrect statement from the following:

1. Baldness is a sex limited trait
2. Galactosemia is an inborn error of metabolism
3. Linkage is an exception to the principle of independent assortment in heredity
4. Small population size results in random genetic drift in a population

Sickle-cell anaemia is:

1. Caused by substitution of valine by glutamic acid in the beta globin chain of haemoglobin
2. An autosomal linked dominant trait
3. Caused by a change in a single base pair of DNA
4. Characterised by elongated sickle like RBCs with a nucleus

The most popularly known blood grouping is the ABO grouping. It is named ABO and not ABC, because "O" in it refers to having:

1. Other antigens besides A and B on RBCs
2. No antigens A and B on RBCs
3. Overdominance of this type on the genes for A and B types
4. One antibody only – either anti-A or anti-B on the RBCs

Study the pedigree chart given below: [figure] What does it show?

1. Inheritance of a recessive sex-linked disease like haemophilia
2. Inheritance of a sex-linked inborn error of metabolism like phenylketonuria
3. The pedigree chart is wrong as this is not possible
4. Inheritance of a condition like phenylketonuria as an autosomal recessive trait

Which one of the following conditions in humans is correctly matched with its chromosomal abnormality/linkage?

1. Klinefelter's syndrome — 44 autosomes + XXY
2. Colour-blindness — Y-linked
3. Down syndrome — 44 autosomes + XO
4. Erythroblastosis foetalis — X-linked

Haploids are more suitable for mutation studies than the diploids. This is because:

1. all mutations, whether dominant or recessive are expressed in haploids
2. mutagens penetrate in haploids more effectively than in diploids
3. haploids are reproductively more stable than diploids
4. haploids are more abundant in nature than diploids

A human male produces sperms with the genotypes AB, Ab, aB, and ab pertaining to two diallelic characters in equal proportions. What is the corresponding genotype of this person?

1. AaBb
2. AABB
3. AaBB
4. AABb

In pea plants, yellow seeds are dominant to green. If a heterozygous yellow seeded plant is crossed with a green seeded plant, what ratio of yellow and green seeded plants would you expect in F1 generation?

1. 9 : 1
2. 3 : 1
3. 50 : 50
4. 1 : 3

Inheritance of skin colour in humans is an example of:

1. Chromosomal aberration
2. Polygenic inheritance
3. Codominance
4. Point mutation

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

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