# Describe how mutations contribute to variation within a population, and explain why most mutations have no effect on the phenotype of an organism.

> AQA GCSE Biology (8461) — 4.6.2 Variation and evolution · Describe · 4 marks

## Mark scheme (4 marks)

1. A mutation is a random change in DNA
2. Mutations may produce new alleles / genetic variants
3. New alleles can lead to different phenotypes / observable characteristics in the population, increasing variation
4. Most mutations occur in non-coding DNA / the mutation does not change the sequence of amino acids / protein produced is unchanged

## Key terms

- [mutation](https://www.gradenine.co.uk/glossary/mutation)
- [phenotype](https://www.gradenine.co.uk/glossary/phenotype)
- [variation](https://www.gradenine.co.uk/glossary/variation)

## Related

- [Revision notes for AQA GCSE Biology (8461)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-how-mutations-contribute-to-variation-0a46853c) · Published by Druglandscape Ltd.