Write short note on Mutation.

Explanation

Mutation is a sudden, stable and inheritable change in genetic material or DNA sequences of an organism.
= The organism, which undergoes mutation is called mutant.
= The chemicals and physical factors that induce mutations are called mutagens. eg. UV radiations etc.
= The mutations are of following types :

Point mutation arises due to change in single base pair of DNA.
= Frame shift mutation refers to deletions and insertions of base pairs in DNA.
= The loss or gain of a segment of DNA, results in structural alteration in chromosomes because genes are located on the chromosomes.
= The alteration in chromosomes results in abnormalities and is common in cancerous cells.
= When the members of a homologous pair of chromosomes fail to segregate during meiosis aneuploidy occurs.
= It means, there is loss or gain of one or more chromosomes.
= Due to this there may be monosomy i.e. lack of one chromosome of normal complement or trisomy i.e. three instead of normal two chromosomes.
= Polyplolidy occurs when there is failure of cytokinesis after telophase stage of cell division resulting in an increase in a whole set of chromosomes in an organism.
= In this phenomenon, the cell has loss or gain of three, four or more sets of chromosomes.
= Further autopolyploids are polyploids with multiple chromosome sets derived from a single species.
= And allopolyploids is where chromosomes are derived from different species i.c. result of multiplying the chromosome number and forming a hybrid.