Change in the sequence of nucleotides in DNA is called:

1. Mutagen

2. Mutation

3. Recombination

4. Translation

Which of the following is the example of a sex-linked disease:

1. AIDS

2. Colour blindness

3. Syphilis

4. Gonorrhoea

A gene is said to be dominant if:

Mangolian idiots are due to trisomy in the 21^st chromosome is called:

1. Down's syndrome

2. Turner's syndrome

3. Kleinfelters syndrome

4. Triplex syndrome

In Drosophila the XXY condition leads to femaleness whereas in human beings the same condition leads to Klinefelter's syndrome in males. It proves:

The linkage map of the X-chromosome of fruitfly has 66 units, with yellow body gene (y) at one end and bobbed hair (b) gene at the other end. The recombination frequency between these two genes (y and b) should be:

1. 60%

2. > 50%

3. ≤ 50%

4. 100%

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

When a cluster of genes shows linkage behaviour they:

1. Do not show a chromosome map

2. Show recombination during meiosis

3. Do not show independent assortment

4. Induce cell division

A genetic map is one that:

1. Establishes sites of the genes on a chromosome

2. Establishes the various stages in gene evolution

3. Shows the stages during the cell division

4. Shows the distribution of various species in a region

Independent assortment of genes does not take place when: