Download DNA (Gene) Mutations

DNA (Gene) Mutations
Gene Mutations
Change in the
nucleotide sequence of
a gene
May only involve a
single nucleotide
May be due to copying
errors, chemicals,
viruses, etc.
How common are mutations?
Mutations occurs at a
frequency of about 1 in every
1 billion base pairs
Everybody has about 6
mutations in each cell in their
body!
If I have that many mutations,
why don’t I look weird?
Mutations are not always seen.
Every part of your DNA doesn’t
make a protein or trait.
Types of Gene Mutations
Include:
Point Mutations
Substitutions
Insertions
Deletions
Frameshift
Point Mutation
Change of a single
nucleotide
Includes the
deletion, insertion, or
substitution of ONE
nucleotide in a gene
DNA (Gene) Mutation
Normal DNA:
CGA – TGC – ATC
Mutated DNA: CGA – TGC - TTC
What has happened to
the normal DNA?
DNA (Gene) Mutation
Normal DNA:
CGA – TGC – ATC
Mutated DNA: CGA – TGC - TTC
*Adenine was accidentally
replaced with thymine
*What is this mutation called?
Substitution
Normal DNA:
CGA – TGC – ATC
Mutated DNA: CGA – TGC - TTC
What will happen to the
amino acids?
Point Mutation
Sickle Cell
disease is the
result of one
nucleotide
substitution
Occurs in the
hemoglobin gene
DNA (Gene) Mutation
Normal DNA:
CGA – TGC – ATC
Mutated DNA: CGA – TAG – CAT - C
What has happened to
the normal DNA?
DNA (Gene) Mutations
Normal DNA:
CGA – TGC – ATC
Mutated DNA: CGA – TAG – CAT - C
*Adenine was inserted,causing the
remaining DNA to shift to the right
*What is this mutation called?
Insertion
Normal DNA:
CGA – TGC – ATC
Mutated DNA: CGA – TAG – CAT - C
What will happen to the
amino acids?
DNA (Gene) Mutation
Normal DNA:
CGA – TGC – ATC
Mutated DNA: CGA – TCA- TC
What has happened to
the normal DNA?
DNA (Gene) Mutation
Normal DNA:
CGA – TGC – ATC
Mutated DNA: CGA – TCA- TC
*Guanine was removed, causing the
remaining DNA to shift to the left
*What is this mutation called?
Deletion
Normal DNA:
CGA – TGC – ATC
Mutated DNA: CGA – TCA- TC
What will happen to the
amino acids?
Frameshift Mutation
Inserting or deleting
one or more
nucleotides
Changes the “reading
frame” like changing a
sentence
Proteins built
incorrectly
Frameshift Mutation
Original:
The fat cat ate the wee rat.
Frame Shift (“a” added):
 The fat aca tat eth ewe
era t.
Amino Acid Sequence
Changed
Gene Mutation
Animation
• What causes mutations?
• What happens to a person who
has a mutation?
• Which mutation would
have the least effect on an
organism?
• When would a mutation
have the most effect on
an organism?