Transcript Mutations

V. Mutations
Mutations
Unfortunately, nature isn’t always perfect. What
happens when things go wrong?
A. What is a mutation?
1. A change in genetic
material
a) Gene (point) mutationa change in a single gene
b) Chromosomal mutationa change in the number
or structure of the
chromosome
B. Gene (point) Mutations
1. To illustrate gene mutations, we’re going to use
this sentence as an example:
THEDOGBITTHECAT
THE DOG BIT THE CAT
2. Point mutations: a change in one or a few
nucleotides on a DNA strand
3. 3 specific types we will discuss include:
a) silent mutation
b) substitution
c) Frameshift mutation (insertion & deletion)
4. Silent Mutations
a) Silent mutations: mutations that change the
DNA sequence, but don’t change the amino
acid sequence produced in protein synthesis.
– This has NO effect on an organism. Why?
THE DOG BIT THE CAT
THE DOG BIT THE KAT
5. Substitution Mutation
a) Substitution mutations do
change the sequence.
THE DOG BIT THE CAT
THE DOG BIT THE CAR
6. Frameshift Mutations
a) Two types of frameshift mutations:
– Insertions
– Deletions
b) Frameshift mutations cause MAJOR changes
to the amino acid sequence – since the
sequence is still read in groups of three.
6. Frameshift Mutations
we’re going to insert another “D”
THE DOG BIT THE CAT
THE DDO GBI TTH ECA
we’re going to delete this “D”
THE DOG BIT THE CAT
THE OGB ITT HEC AT_
C. Chromosomal Mutations
1. Deletions: occurs when a chromosome breaks and a
piece of a chromosome is lost.
Chromosomal Mutations
2. duplication– occurs when part of a chromosome
breaks off and is incorporated into another
chromosome.
Chromosomal Mutations
3. translocation – occurs when parts of two different
chromosomes swap positions.
Chromosomal Mutations
4. Inversions – occurs when part of a chromosome
breaks off, turns around, and reattaches in the
reverse order.
D. How to become
a mutant…
1. Can I become a mutant?
a) Yes, but not like the
comics.
b) Some mutations are
inherited but others
occur later in life as a
result of mutagens.
c) Mutagens are things that
can cause a change in
DNA sequences.
•
•
•
Radiation
Chemicals (think teenage
mutant ninja turtles)
High temperatures
Monster DNA
• Using the knowledge that you have gained this
unit, follow the directions on the WS to create
your monsters!
Homework
• Monster DNA