What types of mutation are there?


What types of mutation are there?

What types of mutation are there?

There are lots of different mutations that can occur in our DNA.

What types of mutation are there?

Small-scale mutations


  • Substitution – when one or more bases in the sequence is replaced by the same number of bases (for example, a cytosine substituted for an adenine).


  • Inversion – when a segment of a chromosome is reversed end to end.


  • Insertion – when a base is added to the sequence.


  • Deletion – when a base is deleted from the sequence.


Large-scale mutations

  • Copy number variation (CNV) is a type of mutation where large chunks of DNA are inserted, repeated or lost. These regions of DNA can be between 10,000 and 5,000,000 bases long.
  • Duplication of genes. When there is an increase in the number of copies of a gene.
  • Deletions of large regions of the chromosome.
  • Loss of one copy of a gene in an organism that previously had two copies.
  • Loss of both copies of the same gene.
  • Movement of sections of DNA from one location to another.
  • Addition of an extra copy of a chromosome. For example, an extra copy/partial copy of chromosome 21 results in Down’s syndrome.

How do we inherit mutations?

  • Each of our genes is a copy from either our mum or our dad. If there is a mutation in one of these genes, this can be passed on from parent to child along with the rest of their genes.
  • Small inherited changes can make big differences to our bodies. For example, the most common mutation to cause cystic fibrosis is the loss of three letters in a gene called CFTR.
  • Even though mutation is common, inherited diseases are relatively rare. This is because inherited diseases are often recessive, which means that a person must have two copies of the mutated gene to get the disease.

Image credits: Genome Research Limited

This page was last updated on 2021-07-21

How helpful was this page?

👎 👍 Send

What's the main reason for your rating?


Which of these best describes your occupation?


how old are students / how old are you?


What is the first part of your school's postcode?


How has the site influenced you (or others)?


Thankyou, we value your feedback!

If you have any other comments or suggestions, please let us know at comment@yourgenome.org


Can you spare 5-8 minutes to tell us what you think of this website? Open survey