---
title: "Genetic Mutation"
description: "Explain genetic mutation as a random change in DNA sequence, describe causes of mutation (e.g. radiation, chemicals, copying errors), and explain that most mutations are neutral, some harmful, and a f"
canonical: https://lightmysky.com/learn/science/genetic-mutation-mt_rOqo-8GeKt
source: https://lightmysky.com/learn/science/genetic-mutation-mt_rOqo-8GeKt.md
retrieved: 2026-10-19
---

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# Genetic Mutation

Explain genetic mutation as a random change in DNA sequence, describe causes of mutation (e.g. radiation, chemicals, copying errors), and explain that most mutations are neutral, some harmful, and a few beneficial

Subject: Science · Area: Ecosystems & Habitats · Ages 12 to 14
Page: https://lightmysky.com/learn/science/genetic-mutation-mt_rOqo-8GeKt

## Ready when they can

- Defines mutation as a change to DNA sequence
- Names at least two things that can cause mutations (mutagens)
- Explains that mutations are the original source of all genetic variation
- Explains that beneficial mutations can be selected for by natural selection

## Lesson: What Is a Genetic Mutation?

You already know your genes are made of DNA, a code written in a chemical alphabet. A mutation is a random change in that code: one letter gets swapped, added, or dropped by accident.

*(drawing: The highlighted letter shows where a copying error swapped a G for an A. That one change is a mutation.)*

Mutations happen a few ways. Cells copy their DNA every time they divide, and copying is nearly perfect but not flawless, so a wrong letter slips in sometimes. Radiation, like the UV light in sunlight, can also damage DNA. So can certain chemicals, like the ones in cigarette smoke.

**Example.** A beetle is born with a mutation that makes its shell slightly darker. On bright sandy ground, this makes no real difference, so the mutation is neutral. But on a shaded forest floor, the darker beetle is harder for birds to spot. That same mutation just became useful.

**Tip.** Most mutations don't change much at all, we call these neutral. A few cause harm. But every so often, one helps an organism survive or reproduce, and natural selection can favor it. That's why mutations are the raw material behind all genetic variation.

**Recap.** A mutation is a random change in DNA caused by copying errors, radiation, or chemicals, and while most are neutral, the rare helpful one can spread through a population.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [Chromosomes, Genes & DNA](https://lightmysky.com/learn/science/chromosomes-genes-and-dna-mt_6aJUzBYGNs)

## Opens up

- [Mutations and Their Effect on Proteins](https://lightmysky.com/learn/science/mutations-and-their-effect-on-proteins-mt_dTOQH3vGSz)
- [How Natural Selection Works](https://lightmysky.com/learn/science/how-natural-selection-works-mt_FuVEZ1Ac9s)