Learning goals
Mutations
Unit 4
Chapter 12-4
Mutation
•  Mutation: permanent change in the
DNA base sequences.
•  Mutations can be good (rarely) but
usually are bad
–  1. Good: make new traits
–  2. Bad: change a protein
structure or gene activity
•  1. Explain what a mutation is and how
it can affect an organism.
•  2. Name the two types of cells where
mutations can occur and the affects.
•  3. Describe the two types of gene
mutations and give examples of each.
Where Mutations Occur
–  Mutations occur in regular body cells
•  1. Occurs during mitosis (cell division)
•  2. Affects the person, not the offspring
•  3. Affects the function of the cell
–  This may cause cancer
Types of Mutations
–  Mutations occur in sex
cells (sperm or eggs)
•  1. Affects the offspring not
the person.
•  2. Usually is a disease.
–  Ex. Tay Sachs disease,
sickle-cell anemia, muscular
dystrophy
–  2. Frameshift Mutations: mutations that cause a
change in the entire amino acid sequence following
the mutation.
Two Types:
•  1. Deletion mutation: when a single nucleotide is removed
–  EX: The fat cat ate the rat.
»  The atc ata tet her at
•  2. Insertion mutation: when a single nucleotide is added
–  EX: The fat cat ate the rat.
»  The fat sca tat eth era t
•  Major effects! May alter the function of a protein.
•  Gene Mutations: A change in the DNA
sequence of a gene (2 types)
–  1. Point Mutations: a change in a single base in
DNA
•  May cause a change in one single amino acid or cause
no change at all.
–  NORMAL DNA
»  DNA:
»  mRNA:
»  A.A.:
–  MUTATION
»  DNA:
»  mRNA:
»  A.A.:
TAC GCA TGG AAT
AUG CGU ACC UUA
Met-----Arg-----Thr-----Leu
TAC GTA TGG AAT
AUG CAU ACC UUA
Met-----His-----Thr-----Leu
•  Chromosomal Mutations: Changes the
number or structure of chromosomes.
–  1. Deletion or duplication of a piece of
chromosome.
–  2. Inversion: a piece of the chromosome will
detach and reattach in reverse order.
–  3. Translocation: a piece of a chromosome will
break off and reattach to an entirely different
chromosome.
Learning goals
•  1. Explain what a mutation is and how
it can affect an organism.
•  2. Name the two types of cells where
mutations can occur and the affects.
•  3. Describe the two types of gene
mutations and give examples of each.