Principles of Inheritance and Variation

Which one of the following disorders is caused by the substitution of Glutamic acid (Glu) by Valine (Val) at the sixth position of the beta globin chain of the haemoglobin molecule ?

1. Phenylketonuria
2. Haemophilia
3. Sickle-cell anaemia
4. Thalassemia

The sixth mutant codon of beta globin gene causing polymerization of Haemoglobin and change in RBC shape is .

1. CAG
2. AUG
3. GUG
4. GAG

Match List I with List II : Choose the correct answer from the options given below :

1. A-I, B-II, C-III, D-IV
2. A-II, B-III, C-IV, D-I
3. A-III, B-IV, C-I, D-II
4. A-IV, B-I, C-II, D-III

If a colour blind female marries a man whose mother was also colour blind, what are the chances of her progeny having colour blindness?

1. 25%
2. 50%
3. 75%
4. 100%

Given below are two statements: In the light of the above statements, choose the correct answer from the options given below :

1. Statement I is incorrect but Statement II is correct
2. Both Statement I and Statement II are correct
3. Both Statement I and Statement II are incorrect
4. Statement I is correct but Statement II is incorrect

A normal girl, whose mother is haemophilic marries a male with no ancestral history of haemophilia. What will be the possible phenotypes of the offspring? Choose the most appropriate answer from the options given below:

1. B and D only
2. A and B only
3. B and C only
4. A and D only

In a cross between a male and female, both heterozygous for sickle cell anaemia gene, what percentage of the progeny will be diseased?

1. 100%
2. 50%
3. 75%
4. 25%

Select the correct match

1. Thalassemia – X linked
2. Sickle cell anaemia – Autosomal recessive trait, chromosome-11
3. Phenylketonuria – Autosomal dominant trait
4. Haemophilia – Y linked

A woman has an X-linked condition on one of her X chromosomes. This chromosome can be inherited by

1. only daughters
2. only sons
3. only grandchildren
4. both sons and daughters

Thalassemia and sickle cell anemia are caused due to a problem in globin molecule synthesis. Select the correct statement.

1. Both are due to a qualitative defect in globin chain synthesis
2. Thalassemia is due to less synthesis of globin molecules
3. Sickle cell anemia is due to a quantitative problem of globin molecules
4. Both are due to a quantitative defect in globin chain synthesis

Pick out the correct statements :

1. A, B and C only
2. A, C and D only
3. A and D only
4. B and D only

Which of the following most appropriately describes haemophilia ?

1. Chromosomal disorder
2. X-linked recessive gene disorder
3. Dominant gene disorder
4. Recessive gene disorder

If a colour-blind man marries a woman who is homozygous for normal colour vision, the probability of their son being colour-blind is

1. 0.75
2. 0.5
3. 0
4. 1

Select the incorrect statement with regard to Haemophilia :

1. It is a dominant disease
2. A single protein involved in the clotting of blood is affected
3. It is a recessive disease
4. It is a sex-linked disease

If both parents are carriers for thalassemia, which is an autosomal recessive disorder, what are the chances of pregnancy resulting in an affected child ?

1. 100%
2. 25%
3. no chance
4. 50%

Represented below is the inheritance pattern of a certain type of traits in humans. Which one of the following conditions could be an example of this pattern ? [figure]

1. Haemophilia
2. Sickle cell anaemia
3. Thalassemia
4. Phenylketonuria

A normal-visioned man whose father was colour-blind, marries a woman whose father was also colour-blind. They have their first child as a daughter. What are the chances that this child would be colour-blind ?

1. 50%
2. 25%
3. 100%
4. Zero percent

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

Both sickle cell anemia and Huntington's chorea are-

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

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

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

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

Haemophilia is more commonly seen in human males than in human females because -

1. This disease is due to an X-linked dominant mutation
2. This disease is due to a Y-linked recessive mutation
3. This disease is due to an X-linked recessive mutation
4. A greater proportion of girls die in infancy

Which of the following is not a hereditary disease?

1. Cretinism
2. Cystic fibrosis
3. Haemophilia
4. Thalassemia

A woman with normal vision, but whose father was colour blind, marries a colour blind man. Suppose that the fourth child of this couple was a boy. This boy -

1. May be colour blind or may have normal vision
2. Must have normal colour vision
3. Must be colour blind
4. Will be partially colour blind since he is heterozygous for the colour blind mutant allele.

A male human is heterozygous for autosomal genes A and B and is also hemizygous for hemophilic gene h. What proportion of his sperms will be abh?

1. 1/16
2. 1/32
3. 1/8
4. 1/4

A normal woman, whose father was colour-blind is married to a normal man. The sons would be :-

1. All colour-blind
2. 75% colour-blind
3. All normal
4. 50% colour-blind

The recessive genes located on X-chromosomes in humans are always -

1. Expressed in females
2. Sub-lethal
3. Expressed in males
4. Lethal