Write a short note on Mutation.

(N/A) Mutation is a sudden,stable,and inheritable change in the genetic material or $DNA$ sequences of an organism.
The organism that undergoes mutation is called a mutant.
The chemical and physical factors that induce mutations are called mutagens,e.g.,$UV$ radiations,$X$-rays,etc.
Mutations are broadly classified into the following types:
$1$. Gene Mutations:
- Point mutation: Arises due to a change in a single base pair of $DNA$.
- Frame-shift mutation: Refers to the deletion or insertion of base pairs in $DNA$,which shifts the reading frame.
$2$. Chromosomal Mutations:
- Structural variation (Aberration): The loss or gain of a segment of $DNA$ results in structural alteration in chromosomes,as genes are located on them. This is common in cancerous cells.
- Numerical variation:
- Aneuploidy: Occurs when the members of a homologous pair of chromosomes fail to segregate during meiosis. This leads to the loss or gain of one or more chromosomes (e.g.,Monosomy: lack of one chromosome; Trisomy: three instead of two chromosomes).
- Polyploidy: Occurs due to the failure of cytokinesis after the telophase stage of cell division,resulting in an increase in a whole set of chromosomes. Autopolyploids have multiple chromosome sets derived from a single species,while allopolyploids have chromosomes derived from different species.