Mutation - A Genetic Change

We know that the genes present in organisms are responsible for structural and functional changes in them. The fundamental unit of hereditary is genes. Besides this, it is the cause of variation in organisms which can be either good or bad cause. Any change in genetic codes may lead to mutation. Here we will discuss mutations, its cause, and types.

Mutation of Genes


Mutation can be defined as a phenomenon of change in the DNA sequence. This can be either due to internal factors or external factors (smoking, UV rays, etc.). It is one reason for the variation of DNA in an organism, the other being recombination. It leads to the alteration in the expression of the genotype and phenotype. Eventually, this may affect cells or damage the organism.


DNA sequences make up the genes of organisms which, in turn, encode for a particular protein. Any fluctuation in this sequence, for example, mistakes during DNA transcription, may lead to a change in the genetic codes, which results in the alteration of encoded proteins. Compared to the mutations of RNA and proteins, DNA mutation is more serious.


 Any change in the DNA helical structure is a cause of mutation. In other words, when a segment or base pair of a DNA is either deleted or inserted, it may lead to chromosome abnormalities or aberrations. Developments of cancerous cells are due to these chromosomal aberrations.


Mutation is of different types based on the range of alternation. It can begin with a single base pair to a segment of DNA. Also, they can be either hereditary i.e., inherited from parents or can be acquired due to environmental factors. And a factor that leads to alternation is called mutagens.

Point mutation

A point mutation is a type of variation due to a change in the building block, base pair of DNA, e.g. Sickle cell anemia. Frame-shift mutation is the removal or addition of base pairs of DNA.

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Practise This Question

Which of the following is an example of discontinuous variation?