Principles of Inheritance and Variation · Question 81

In our society women are blamed for producing female children. Choose the correct answer for the sex-determination in humans.

1. Due to some defect like aspermia in man
2. Due to the genetic make up of the particular sperm which fertilizes the egg
3. Due to the genetic make up of the egg
4. Due to some defect in the women

Which one is the incorrect statement with regards to the importance of pedigree analysis?

1. It confirms that DNA is the carrier of genetic information
2. It helps to trace the inheritance of a specific trait
3. It confirms that the trait is linked to one of the autosome
4. It helps to understand whether the trait in question is dominant or recessive

Down's syndrome in humans is due to :

1. Three 'X' chromosomes
2. Monosomy
3. Three copies of chromosome 21
4. Two 'Y' chromosomes

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 test cross is carried out to :

1. Determine whether two species or varieties will breed successfully
2. Determine the genotype of a plant at F2
3. Predict whether two traits are linked
4. Assess the number of alleles of a gene

Which one of the following is a wrong statement regarding mutations ?

1. UV and gamma rays are mutagens
2. Deletion and insertion of base pairs cause frame-shift mutations
3. Cancer cells commonly show chromosomal aberrations
4. Change in a single base pair of DNA does not cause mutation

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

F2 generation in a Mendelian cross showed that both genotypic and phenotypic ratios are same as 1 : 2 : 1. It represents a case of

1. Monohybrid cross with incomplete dominance
2. Co-dominance
3. Monohybrid cross with complete dominance
4. Dihybrid cross

Which one of the following conditions of the zygotic cell would lead to the birth of a normal human female child?

1. only one Y chromosome
2. only one X chromosome
3. one X and one Y chromosome
4. two X chromosomes

Test cross in plants or in Drosophila involves crossing:

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