Point Mutations

A mutation is a random change in the base sequence of a DNA molecule.

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Mutations

Mutations happen during DNA replication as a result of errors that are not repaired.

Mutagens - agents from the environment, such as radiation and chemicals.

Mutagens can lead to cancer.

Causes of Mutations

Silent Mutations - mutations that have no effect on body cells.

Mutations can create new genes that play a role in evolution.

Significance of Mutations

Point Mutation - a change in one or a very few nucleotides in a gene sequence.

Can have little to no effect on an organism.

Point Mutation

There are 3 types of point mutation:

• Substitution

• Insertion

• Deletion

Point Mutation

Substitution - one base is substituted for another.

Can be harmful or beneficial.

Frameshift Mutations - changes the reading frame of the mRNA sequence.

Types of frameshift mutations:

• Deletion

• Insertion

Frameshift Mutations

Deletion - one or more bases are lost from a DNA sequence.

​​Deletion

Insertion - when one or more bases are inserted into DNA.

​​Insertion