Principles of Inheritance and Variation

In a testcross involving F1 dihybrid flies, more parental-type offspring were produced than the recombinant-type offspring. This indicates

1. Both of the characters are controlled by more than one gene
2. The two genes are linked and present on the same chromosome
3. The two genes are located on two different chromosomes
4. Chromosomes failed to separate during meiosis

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

The mechanism that causes a gene to move from one linkage group to another is called

1. crossing-over
2. translocation
3. duplication
4. inversion

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

A true breeding plant is -

1. produced due to cross-pollination among unrelated plants
2. one that is able to breed on its own
3. near homozygous and produces offspring of its own kind
4. always homozygous recessive in its genetic constitution

The movement of a gene from one linkage group to another is called

1. inversion
2. translocation
3. duplication
4. crossing over

Alleles are

1. true breeding homozygotes
2. different phenotype
3. heterozygotes
4. different molecular forms of a gene

Multiple alleles are present

1. on different chromosomes
2. at the same locus of the chromosome
3. at different loci on the same chromosome.
4. on non-sister chromatids

A man with blood group ‘A’ marries a woman with blood group ‘B’. What are all the possible blood groups of their offsprings?

1. A and B only
2. A, B, AB and O
3. A, B and AB only
4. O only

How many pairs of contrasting characters in pea plants were studied by Mendel in his experiments?

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