Transcript mutation - Doktorscience

Mutation!!!
Causes: mutagens
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Biological viruses disrupt instructions stored
in genes by attaching to the DNA and
interfering
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As a result things can get misread or copied
incorrectly
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Other examples are:
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– Cigarette smoke
– Radiating (x rays or UV rays)
– Mercury
Mutagens can upset the life cycle of a cell and
even cause Cancer
Gene mutations
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A gene mutation is a change in the order of the
A, G, C and T bases in a gene
This can result from
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a base left out of sequence (deletion)
 an extra base added (addition)
 one base substituted for another
(substitution)
Gene mutations can be positive, negative or
neutral
Some mutations can be passed on to offspring
Spirit bear
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Most black bears are black (which I am sure
you guessed)
There is a mutation in 1 out of 10 of the
population of kermode bears (a subspecies of
black bears) that turns the coat white
This is the result of amutation on just ONE base
in the gene for coat colour
To have a white coat, both parents must carry
the altered gene
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The spirit bear is an example of a neutral
mutation
The mutation does not appear to help or hinder
the organism that has it
The most common types of gene mutations are
neutral mutations
Now do the activity on pg 137 in your books :)
You have 15 minutes
Positive mutation
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HIV is a dangerous virus that will lead to AIDS
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There is still no known cure or vaccine
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However, a small percentage of the population
has a mutation that makes them resistant to HIV
This is the result of a mutated gene that
contains the instructions for a protein that
prevents HIV infection
Negative Mutations
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Cystic fibrosis is a genetic disease caused by a
mutation
In cystic fibrosis, mucus builds up because of a
malfunctioning protein
This leads to difficulty breathing, lung
infections and can cause death
Daily antibiotics and physical therapy are
needed to prevent lung infections
Now for a video on a mutation that is both
negative...and positive!
Sickle cell anemia is a “negative” mutation that
affects the hemoglobin in red blood cells.
It is the result of a substitution of the base A
for the base T
Sickle cell anemia video