Mutations

Definition

• A mutation is a change in an organism’s DNA– Silent mutations are changes that do not

result in a change to the organisms phenotype

–Mutations that occur in germ cells (sperm, eggs) are passed on to offspring

–Mutations in somatic (body) cells may be harmless, or may result in disease such as cancer

Chromosomal Mutations

A Point Mutation Resulting in Nonsense

A Point Mutation: An Analogy

t h e r e d d o g b i t t h e t a n c a t

t h e r e d m o g b i t t h e t a n c a t

This point mutation changes the meaning, resulting in nonsense

A Point Mutation Resulting in Missense

A Point Mutation: An Analogy

t h e r e d d o g b i t t h e t a n c a t

t h e r e d h o g b i t t h e t a n c a t

This point mutation changes the meaning, resulting in missense

An Insertion Mutation in a Gene

An Insertion Mutation: An Analogy

t h e r e d d o g b i t t h e t a n c a t

t h e r e d r d o g b i t t h e t a n c a

This insertion mutation changes the reading frame

A Deletion Mutation in a Gene

An Deletion Mutation: An Analogy

t h e r e d d o g b i t t h e t a n c a t

t h e r e d o g b i t t h e t a n c a t _

This deletion mutation changes the reading frame

A Frameshift Mutation