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Learning Outcomes:
The student will explain that during sexual
reproduction, changes in genes (mutations)
of sex cells can cause changes in
characteristics that are inherited.
The student will discuss examples of
beneficial and harmful mutations.
When genes change Image that your
friends invite you to ride on a new roller coaster, but before you climb into the front car, they tell you that some of the metal pars on the coaster have been replace by plastic parts.
Would you still want to ride this roller coaster?
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WHAT ARE MUTATIONS?
_______________ are changes in the genetic
material.
MUTATIONS
mistakes
Mutations can happen when cells make
_____________ in copying their own DNA or
be caused by _______________ or ___________ in the environment.
radiationchemicals
Mutation = Are random changes in an organism’s DNA
Substitution like the ones in the roller coaster can
accidentally happen in DNA. Mutations are changes in
the number, type, or order of the bases on a piece of
DNA that may or may not affect phenotype and
genotype.
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HOW DO MUTATIONS HAPPEN?
Mutations can be INHERITED. This means that if a parent has a mutation in his or her DNA, then the mutation is passed on to his or her children.
Mutations can be ACQUIRED. This happens when environmental agents damage DNA, or when mistakes occur when a cell copies its DNA prior to cell division. Mutation can be caused by mutagens: Which are physical or chemical agents that can cause mutations.
Mutations happen regularly because of random errors when DNA is copied. Damage to DNA can be caused by abnormal thing that happen to cells.
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KINDS OF MUTATIONS
BENEFICIAL MUTATIONSa mutation in an
organism's genome that produces a beneficial effect.
Ex: Disease resistance, endurance, strong
bones, etc.
NEUTRAL MUTATIONS
No change for instance: eye
color, birth marks.
HARMFUL MUTATIONS
Production of inferior or no
proteinResult: Genetic
Diseases, dysfunctional proteins, etc.
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Chromosomal Mutations
Changes in number and structure of entire chromosomes, Chromosomal mutations affect many genes.
Original Chromosome ABC * DEF
Deletion AC * DEF
Duplication ABBC * DEF
Inversion AED * CBF
Translocation ABC * JKL GHI * DEF
Examples:
Trisomy 21 (Down Syndrome)
Turner’s Syndrome
Chromosomal abnormalitiesNondisjunction
• chromosomes don’t separate properly during
meiosis so chromosomes aren’t divided evenly
into sperm or egg cells
OR
Structural abnormalities -shape/structure is incorrect
• deletion
• duplication
• inversion
• translocation
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Chromosomal mutations
Gene deletion: Loss of chromosome sections
A B C D E
Gene duplication: Duplication of chromosome sections
EC DBA C DC DBA E
F
Inversion: Flipping of parts of chromosomes
C DBA E
Translocation: Movement of one part of a chromosome to another part
BA C D E
WX ZY F
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Chromosome Mutation Summary
A karyotype is simply a picture of a person's chromosomes. In order
to get this picture, the chromosomes are isolated, stained, and
examined under the microscope.
What is a Karyotype?
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Learning Check No 1. (Shoulder partner-4 minutes.) Use the picture of this karyotype and discuss the possible answers with your
partner
1. How many chromosome does each human have?
2. How many chromosomes are depict in this picture?
3. Hypothesize, what might have caused this extra chromosome and how do
you predict this might affect the person?
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TYPES OF MUTATONS
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Mutations can be Beneficial Some mutations can provide an advantage
which helps the organism survive
Beneficial Mutations “Polymorphisms”: occurs
when two or more clearly different phenotypes exist in the same population of a species — slight variations in a gene that make us different, ex: eye colors, blood types, etc.
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Muscle bound: Gene mutation for
muscle growth.
A baby Superman, with bulging arm and leg muscles. Not yet 5, he
has muscles twice the size. DNA testing showed why: The boy has a
genetic mutation that boosts muscle growth.
Some mutations do not effect the organism’s
survival (the mutation does not help or hurt
the organism)
Mutations can be NEUTRAL
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Neutral Mutation: Color Variation
Harmful Mutations- Joined Parts
An example of webbed toes sometimes seen in
Andersen's Syndrome, caused by a gene mutation.
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Seven-Legged Frog Three-Legged Duck
Two-Faced Pig
Two-headed snake
Mutation: Extra parts
Polydactyl
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Mutation: extra parts
• Chang and Eng Bunker
• Born in 1811
• In modern times, they could have
easily been separated
• Died on the same day in 1874
Conjoined Twins
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Let’s talk about Inherited Genetic
Diseases
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Genetics diseases can be inherited as the result of a single
defective gene form one parent ( dominant inheritance) or
when the parent contributes a copy of the same defective
gene (recessive inheritance). Sometimes a recessive gene
can be partially expressed and a mild from of the disease
occur.
What causes an inherited disease?
disease allele
disease allele
2 recessive disease alleles(one from each parent)
inherited disease
=
Down’s Syndrome Caused by non-disjunction
of the 21st chromosome. This means that the individual has a extra chromosome
SymptomsLow muscle tone, Looseness of joints, small skull and slanting eyes.In addition, down syndrome always involves some degree of mental retardation.
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Sickle Cell Disease- recessive allele
• The red blood cells, become crescent or sickle shaped.
• Issues with circulation, causing anemia and pain.
• As a result, the red blood cells function abnormally and cause small blood clots.
Turners Syndrome• 1 in 5,000 birthsSymptoms• Narrow hips,broad shoulders and neck.• Females have
undeveloped bodies.
• 45 chromosomes X only
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Hemophilia
Hemophilia hereditary bleeding disorder.
Caused by a recessive gene on the X chromosome.
The severity of hemophilia is related to the amount of the clotting factor in the blood.
.
Cystic fibrosis
.
A person with cystic fibrosis
has breathing difficulties.
They are at risk of repeated
chest infections which can
lead to lung damage.
People with cystic fibrosis
need daily physiotherapy,
which involves massage to
help loosen the sticky
mucus
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Progeria Genetic disorder that results in accelerated
aging
Caused by spontaneous mutations in autosomes
Huntington’s Disease
Huntington's is an inherited
disease that affects the brain
and nervous system
Causes damage to nerve
cells in the areas of the brain
involved in the control of
movement and motivation
The symptoms include :
tremor, clumsiness, lack of
concentration, problems
remembering things,
depression, and mood
changes.
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Phenylketonuria or PKU Phenylketonuria is a birth
defect that causes an amino acid called phenylalanine to build up in your body. Phenylketonuria is caused by a mutation in a gene that helps create the enzyme needed to break down phenylalanine.
People with phenylketonuria (PKU) — babies, children and adults — need to follow a diet that limits phenylalanine, which is found mostly in foods that contain protein. Other wise mental retardation can occur.
Albinism
Albinism Patients are unable to produce skin or eye pigments, and thus are light-sensitive.
The altered gene does not allow the body to make the usual amounts of a pigment called "melanin".
Cause: homozygous recessives genes
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CANCERS
Cancer occurs when cell division gets out of control.
Causes: exposure to some environmental factors : e.g. tobacco smoke or genetic predisposition
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Blue People of Troublesome Creek Blue People of Troublesome Creek • 1820 - French orphan Martin Fugate settled in
Troublesome Creek, later he married
Elizabeth Smith They had 7 children of whom
4 reported to be ‘blue’
• The Fugate offspring had a genetic condition
which was passed down through a recessive
gene and blossomed through intermarriage.
• This mutation causes the hemoglobin to not
been able release oxygen effectively to body
tissues. Patients' lips are purple, the skin looks
blue and the blood is "chocolate colored"
because it is not oxygenated,
• The disorder can be inherited, as was the
case with the Fugate family, or caused by
exposure to certain chemicals.
The Blue People of Kentucky
What is a mutation?
Explain what happens
during deletion
Explain what happens
during duplication
Explain what happens
during translocation
Learning Check No 3 ( Class activity- 8 min)
Find someone who. Stand up and ask everybody in the class the
next questions, use this handout and textbook to answer.
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Can you solve the mystery?
Genetic Detectives
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Genetic Detectives
Dr. Jones needs your help
Mystery disease
You must:
Read about the
condition
Use the disease charts
provided by your
teacher
Determine how the
mystery disease affects
the body
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Mysterious Disease symptoms
The patient doesn’t remember information or preform simple tasks. This is a mild mental illness. There is a loss of motor control as well as physical an mental abilities. At the end the nervous system degenerates irreversibly.
1. Read through the
patient description
2. Write-down any clues,
possible symptoms and
Possible causes
Can you infer which disorder the patient has?
LEARNING CHECK No 4 ( Shoulder partners- 5 minutes)
What’s your diagnosis?
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Write a letter to the patient (Emma) that:
Identify the disorder
Explains what is a genetic mutation
Explains the symptoms, patterns of inheritance, and the description of the defect.
Explains why this disorder is harmful, neutral or beneficial mutation.
Learning Check No 5 Your Task Independent Work – (10 minutes)
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