Changes in DNA and Their Impacts

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Changes in DNA and Their Impacts
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Analogy

• We will be using a sentence as an analogy
  representing a strand of DNA.
• Our sentence is
• The fat cat ate the wee rat.
•  
• If this sentence represents a strand of DNA, what
  does each word represent?
•  
• What does each letter represent?

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Mutations?!?

• Now were going to look at mutations in the DNA.
•  
• When you hear about mutations, you may think
  about some teenage turtles or growing an extra
  arm, but the word mutate just means change. Lets
  look at what happens when we change the
  sentence/DNA.

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Substitution

• The fat cat ate the wee rat.
• The fat cat ate the wet rat.
•  
• What changed?
• What does this represent?
• How would this type of change affect the protein?

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Deletion

• The fat cat ate the wee rat.
• The fat cat att hew eer at.
•  
• What changed?
• What does this represent?
• How would this type of change affect the protein?

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Insertion

• The fat cat ate the wee rat.
• The fab tca tat eth ewe era t.
•  
• What changed?
• How would this type of change affect the protein?

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Point Mutations vs. Frameshift Mutations

• The substitution example was a point mutation.
• These last two examples of deletion and insertion
  were frameshift mutations.
•  
• Whats the difference between a point mutation
  and a frameshift mutation?
• Which is worse? Why?

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Inversion

• The fat cat ate the wee rat.
• The fat tar eew eht eta tac.
•  
• What changed?
• How would this type of change affect the protein?

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Chromosomal Mutations
What changed? How would this type of change
affect the protein?
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Non-disjunctionEx Trisomy 21 or Down Syndrome

• Sometimes there is an error in meiosis when egg
  or sperm cells divide resulting in too many or
  too few chromosomes.
• How do you think this type of change would impact
  protein synthesis?

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Mutation Impact

• The impact of a mutation on an individual also
  depends on where and when it occurs.
•  
• If there was a mutation in the DNA of a zygote,
  how would that impact the individual?
• How might a mutation in a skin cell affect an
  individual?