Question

List the different ways by which mutations alter the structure of the chromosomes. Illustrate any one of them by a diagram.

Answer 1

Mutations alter chromosome structure in several ways:

1. Deletion (Deficiency) – loss of a chromosome section.
2. Duplication – extra copies of a chromosome segment.
3. Translocation – transfer of a chromosome segment to a non-homologous chromosome.
4. Inversion – a chromosome segment rotates 180° on its axis, changing gene order without loss or gain.

Illustration of Deletion:

A chromosome loses a segment, resulting in missing genes. For example, ABCDEFG becomes ABDEFG after deletion of ‘C’.

This deletion disturbs genetic balance and affects phenotype.

Diagram shows a chromosome with a missing part labeled “deletion” indicating the lost section.

These mutations change gene content or arrangement impacting genetic information and organism traits.