Download Mutations - West Ada

Mutation Notes:
Brainstorm the following question:
 What is a mutation?
Think about this as you read…

Open your book to page 136 and quietly
read the section titled: Mutations (pgs.136-137)
with the person sitting next to you.
Mutations

A mutation is any change in a gene or
chromosome.
A mutation in a body cell (somatic), such as
a skin cell, will not be passed on to the
offspring.
 A mutation in a sex cell (hereditary) can be
passed on to an offspring.

Types of Mutations

One or more base substitutions:



One or more bases are deleted:


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Original sequence: ATTCGG
Substitution:
ATTAGG
Original sequence: ATTCGG
Deletion:
ATTGG
Chromosomes fail to separate during meiosis.


Too many chromosomes
Not enough chromosomes
Effects of mutations

A mutation is harmful if it reduces an
organisms chance for survival or reproduction.

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A mutation is helpful if it increases an
organisms chance of survival or reproduction.


Example: Down Syndrome is caused by having 3
chromosomes instead of 2 in the 21st pair.
Example: Sickle-cell disease is caused by a codominant
allele. If you get one allele, you are resistant to Malaria.
Some mutations are neutral.

Example: Albinism, caused by a recessive allele, results
in lighter skin and hair pigment.
Read Environmental Factors on
Genetics

Read page 150 with the person sitting next to
you.
 What environmental factors affect genetics?
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Diet
Skill development
Climate