Mutations
and
Genetic Modifications
TEKS BIO 6C
Eagle Zone (Explain)- don’t be lazy!
Use a book if you don’t know the answer
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Use the words codon, amino
acids, and protein in ONE
sentence which describes their
association with each other.
Why does DNA not participate
directly in protein production?
What is a mutation?
Are all mutations harmful? Why
or Why not?
Can mutation be helpful? How?
Engage: One Wrong Letter
Explore:
What about Mistakes??
Mutation
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Any changes to the genetic
material of a cell
Modeling Chromosomal Mutations
(coloring activity)
Mutations
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How can mutation occur?
Simple replication errors in DNA
 Environmental Mutagens
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How Mutations Happen
Types of Mutations
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Point Mutations
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Base Pair Substitutions
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Base Pair Insertions and deletions
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Silent
Missense – new protein (Amino Acid Substitutions)
Triplet Repeats
Frameshift Mutations
Variation in Chromosome Number
Chromosome Abnormalities
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Deletions
Translocations
Duplications
Inversions
Point Mutations
Potential Results of Point Mutation
 Look at your codon chart or
codon wheel.
 What would happen if the
following Point Mutation
Occurred:
 CCACCC
 GGAGGU
 UCUUCA
 Amino acid meaning was not
altered
 Silent mutation
Potential Result of Point Mutation
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One Amino Acid Substituted for
Another
Sickle Cell Anemia
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Valine is replaced with Glutamic Acid
Point Mutations:
Frame Shift
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One or more bases are inserted or deleted into the
sequence of the gene
How many letters of DNA can a ribosome read at one
time?
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three letter "words”
adding or removing one letter changes each subsequent “word”
These mutation can make the DNA meaningless
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shortened and functionless protein
Deletion
Frame Shifts
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A deletion of
one or more
bases on a
section of the
chromosome.
Base Pair Insertions
(Triplet Repeats)
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Occurs when
DNA is not
copied correctly
and a segment
is repeated
Ex) Huntington
Disease—CAG
Repeat
Variation in Chromosome Number
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Having any
number of
chromosomes
that does not
equal 23 pairs.
Ex) Down
Syndrome –
3 Chromosome
21’s
Chromosome Abnormalities
-Translocations
-Duplications
-Inversions
Translocations
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When one piece of
a chromosome
breaks off and
attaches to
another
chromosome
Duplications
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Occurs during crossing over and
one chromosome ends up with
more genes than it received.
Inversions
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A reversal in the order of a
segment of a chromosome
Heredity, Mutations, and
Inheritable Diseases
Elaboration 1
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The next several slides will give
you information concerning a
particular mutation. On your
paper describe the overall affect
this mutation may cause.
Types of Mutations
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DNA Sentence -
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Mutation -
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If this was a DNA sequence, what would this type of
mutation be called?
Could this change cause the polypeptide sequence to
change? How?
If this type of mutation occurred, what, if any, might be
the possible consequence for the organism?
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THE FAT CAT ATE THE WEE RAT
THE FAT HAT ATE THE WEE RAT
Types of Mutations
- THE FAT CAT ATE THE WEE RAT
THE FAT KAT ATE THE WEE RAT
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Original Sample Gene
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Mutation -
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If this was a DNA sequence, what would this type of
mutation be called?
Was the meaning of the gene sentence altered?
If this type of mutation occurred, would there be any
consequence for the organism?
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Types of Mutations
- THE FAT CAT ATE THE WEE RAT
THE FAT CAA TET HEW EER AT
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Original Sample Gene
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Mutation -
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If this was a DNA sequence, what would this type of
mutation be called?
Could this change cause the polypeptide sequence to
change? How?
If this type of mutation occurred, what, if any, might be
the possible consequence for the organism?
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Types of Mutations
- THE FAT CAT ATE THE WEE RAT
THE FAT ATE THE WEE RAT
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Original Sample Gene
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Mutation -
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If this was a DNA sequence, what would this type of
mutation be called?
Could this change cause the polypeptide sequence to
change? How?
If this type of mutation occurred, what, if any, might be
the possible consequence for the organism?
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Types of Mutations
- THE FAT CAT ATE THE WEE RAT
THE FAT CAT XLW ATE THE WEE RAT
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Original Sample Gene
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Mutation -
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If this was a DNA sequence, what would this type of
mutation be called?
Could this change cause the polypeptide sequence to
change? How?
If this type of mutation occurred, what, if any, might be
the possible consequence for the organism?
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Elaboration 2
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You will watch the movie
Lorenzo’s Oil and complete the
film guide questions.
This film will review several
concepts we have already
covered and will introduce
several new concepts to be
learned.
Evaluation
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The next several slides will
show different types of
mutations.
In your lab book, name each of
the following mutations.
What Type of Mutation?
Genetic Modification
Where can it lead?
Eagle Zone- Complete this
orally-5 minutes
Review questions:
How many bases does it take to make a codon?
3
What are the building blocks of proteins?
Amino acids
What is used to look up amino acids codes?
mRNA codon chart
Evaluate 2- PICTURE IT!
Modeling Mutations Card Activity
• Students will receive cards, representing nucleotides, and line
the cards up in a particular genetic sequence
PART 1
• Students will use colored paper to write the mutated sequences
for these mutations:
– Deletion
– Insertion (insert any new base into the sequence)
– Base Repeat (repeat any single base 3 times)
• Take a picture of the sequence after completing each mutation
PART 2
• Students will use colored paper to:
– Write the mRNA sequence
– Write the amino acid sequence
• Take a picture of these sequences when complete
Karyotyping and
Pedigrees
TEKS BIO 6D
What is a Karyotype
A Karyotype is
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An organized
profile of a
person’s
chromosomes
represented by
a picture of the
person’s
individual
chromosomes
Reading Chromosomes
Characteristics
 Chromosomes are
arranged and
numbered by size,
banding pattern, and
centromere position
 Size ranges from
largest chromosome to
smallest chromosome
What is the purpose of a karyotype?
To help scientists quickly identify chromosomal
alterations that may result in a genetic disorder
Elaborate/Extend
•Class practice: match the chromosomes with their
correct sister in the online game
CLASS PRACTICE
•Karyotyping Activity: Match chromosome parts in
the envelope with the karyotype your group is
given. This activity will help you practice
understanding what causes genetic disorders and
will serve as an introduction to mutations
Pedigrees
What is a pedigree?
•similar to a family tree
•Shows genotypes and phenotypes of
a genetic trait through several
generations of a family
Molecular Genealogy Animation
Pedigree Analysis
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Autosomal Recessive Inheritance
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a pattern of inheritance resulting from the
transmission of a recessive allele on an autosome (a
chromosome other than a sex chromosome)
Males and females are affected with equal frequency
There may be no family history of the trait; it becomes
manifest when two carriers have a child who is
homozygous recessive
Examples are:
 Cystic fibrosis, phenylketonuria, and galactosemia
Pedigree Analysis
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Autosomal Dominant Inheritance
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a pattern of inheritance in which the transmission of a
dominant allele on an autosome causes a trait to be
expressed
Males and females are affected with equal frequency
If one parent is homozygous for the dominant allele,
all of the children will express the trait
Examples:
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Achondroplasia, osteogenesis imperfecta, polydactyly,
Marfan's syndrome, and some neuromuscular disorders
Elaborate/Extend
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Family Pedigrees activity
Utah website for practice and more information on your disorder:
http://learn.genetics.utah.edu/
Explain
Meiosis- Making Reproductive
Cells (Sperm and Eggs)
Event
Mitosis
Meiosis
Two cell divisions
Centrioles appear
Chromosomes pair up
Spindle fibers form
Cytokinesis
Two daughter cells
Four daughter cells
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Draw the chart into your lab book. Fill in the
chart as we watch the animation.
Meiosis Animation
Explore- Modeling MeiosisStraw activity
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Use yarn to represent cell
membrane and nuclear
membrane (when present)
Cut out straws of different colors
to represent the phases of
meiosis 1 and meiosis 2.
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Use your Phases of Meiosis notes
as a guide