Principles of Inheritance and Variation

In a plant, red fruit (R) is dominant over yellow fruit (r) and tallness (T) is dominant over shortness (t). If a plant with RRTt genotype is crossed with a plant that is rrtt

1. 75% will be tall with red fruit
2. 25% will be tall with red fruit
3. 50% will be tall with red fruit
4. All the offspring will be tall with red fruit

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

Lack of independent assortment of two genes A and B in fruit fly Drosophila is due to

1. Linkage
2. Recombination
3. Repulsion
4. Crossing over

One of the parents of a cross has a mutation in its mitochondria. In that cross, that parent is taken as a male. During segregation of F2 progenies that mutation is found in -

1. 50% of the progenies
2. 1/3 of the progenies
3. None of the progenies
4. All the progenies

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

After a mutation at a genetic locus the character of an organism changes due to the change in :-

1. Protein synthesis pattern
2. RNA transcription pattern
3. DNA replication
4. Protein structure

In a mutational event, when adenine is replaced by guanine, it is a case of -

1. Frameshift mutation
2. Transition
3. Transversion
4. Transcription

Which one of the following traits of garden pea studied by Mendel was a recessive feature?

1. Green seed colour
2. Green pod colour
3. Axial flower position
4. Round seed shape

The genes controlling the seven pea characters studied by Mendel are now known to be located on how many different chromosomes?

1. Six
2. Seven
3. Five
4. Four