How do DNA mutations occur?

DNA are changes in the nucleotide sequence.
They can occur in many different ways such as when cells are exposed to too much radiation chemicals or in many cases as random copying errors during cell division. As a result of this your DNA will get changed in ways that are typically harmful to the cells but mutations can be sometimes be helpful when they increase variation .
Types of mutation:
Causes of mutation:
Examples of mutations include:
– cancer: the spontaneous and uncontrollable division of cells
– green eyes
– Downs syndrome: the addition of an extra chromosome 47 instead of 46.
There are three types of mutation harmful neutral and useful mutations. Harmful mutations are those that have negative effects on humans neutral mutations have no effect on the organism and useful mutations are those that benefit the organism and put it above other organisms of the same type in the evolutionary tree.