Principles of Inheritance and Variation

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

An abnormal human baby with ‘XXX’ sex chromosomes was born due to

1. formation of abnormal sperms in the father
2. fusion of two ova and one sperm
3. formation of abnormal ova in the mother
4. fusion of two sperms and one ovum

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%

If two persons with 'AB' blood group marry and have sufficiently large number of children, these children could be classified as 'A' blood group : 'AB' blood group : 'B' blood group in 1 : 2 : 1 ratio. Modern technique of protein electrophoresis reveals presence of both 'A' and 'B' type proteins in 'AB' blood group individuals. This is an example of :

1. Codominance
2. Partial dominance
3. Incomplete dominance
4. Complete dominance

Which idea is depicted by a cross in which the F1 generation resembles both the parents?

1. law of dominance
2. co-dominance
3. incomplete dominance
4. inheritance of one gene

Which of the following statements is not true of two genes that show 50% recombination frequency ?

1. The genes are tightly linked
2. The genes show independent assortment
3. If the genes are present on the same chromosome, they undergo more than one crossovers in every meiosis.
4. The genes may be on different chromosomes