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MUTATIONS
Changes in DNA that affect genetic
information
How unique is your DNA?
 You share 100% of the same genes as
all other humans.
 The reason you are different is that you
have different forms of these genes.
 You share 98% of the same genes as a
chimpanzee.
 You share 92% of the same genes as a
mouse or any other mammal.
Monstrous Mutations
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Are we using all of our
DNA?
 Scientists estimate that less than 10% of
our DNA is actually ‘functional’ and
providing the instructions the body needs
to survive
 Some sections of our DNA repeat codes
over and over again; other parts hold
genes that are inactive
How are your traits
decided?
 The order of nitrogen bases in your DNA
determines your traits
 Different orders of bases code for
different forms of each gene
 Ex: If you take the letters M, A, N, E, you
can make different words that look and
sound differently.
MANE, MEAN, NAME, AMEN
Sometimes changes in
DNA just happen.
 Our DNA can change without warning,
which changes the genes and how they
behave.
 Factors that cause changes in our DNA:
 Errors when DNA is copied for new cells
 Environmental factors change DNA
(nicotine, sunlight, x-rays, chemicals
 Mutations are inherited from the parents
Monstrous Mutations
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Define mutation
 A mutation is any change in the
sequence of bases in an organism’s DNA
Not all mutations are bad!
 When ‘coded’ regions of DNA have mutations,
a few results can occur:
 Negative effect – organism’s chance of survival
decreases (Tay-Sachs disease, animal in wild born
with two heads)
 Neutral effect – organism’s chance of survival is
not affected (human born with extra toe, gluten
intolerance, birth marks, eye color)
 Beneficial effect – organism’s chance of survival
increases (carriers of sickle cell gene are resistant
to Malaria, people with a mutated osteoporosis
genes have super-strong bones)
Genetic Diseases /
Disorders
 A genetic disease or disorder is an illness
caused by a mutated gene or by a
damaged chromosome pair
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Chromosome Mutations
 Down Syndrome
 Have an extra 21st
chromosome.
 Children with Down
Syndrome develop
slower, may have
heart and stomach
illnesses and vary
greatly in their
degree of
intelligence.
Sex Chromosome
Abnormalities
 XYY Syndrome
 Normal male traits
 Often tall and thin
 Associated with antisocial and behavioral
problems
Can you give yourself
cancer?
 Our behaviors
may be putting
ourselves at risk
 Exposing
ourselves to
mutagens
(nicotine, sunlight,
radiation)
Monstrous Mutations
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Cancer
 Illness caused by
uncontrolled cell
growth that take
over healthy cells
 Most are caused
by random
mutations or
environmental
factors
Characteristics of Cancer
 Avoids cell death
 Doesn’t listen to
body’s ‘STOP’
growing signals
 Able to spread to
other areas of the
body
Causes of Cancer
 Inherited from
parents
 Radiation (UV, xrays)
 Chemicals
(nicotine,
asbestos, arsenic)
Monstrous Mutations
Time!