DNA Mutations. What if this DNA CACGTGGACTGAGGACTCCTC was changed to this DNA?...
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Transcript of DNA Mutations. What if this DNA CACGTGGACTGAGGACTCCTC was changed to this DNA?...
DNA Mutations
What if this DNA…
CACGTGGACTGAGGACTCCTC
…was changed to this DNA?
CACGTGGACTGAGGACACCTC
What if this DNA…
CACGTGGACTGAGGACTCCTC
…was changed to this DNA?
CACGTGGACTGAGGACACCTC
What does it matter???
CACGTGGACTGAGGACTCCTCCodon for CTC =
glutamate
CACGTGGACTGAGGACACCTCCodon for CAC =
valine
What does it matter???
Mutation = any change in a DNA sequence- usually happens during DNA replication- in sex cells, it may affect individual’s
offspring/children- in body cells, it may affect the individual
Mutations can:- be bad, leading to cancer, aging, birth
defects, self-aborted embryos
- be good, making an organism survive better in its environment- Example: bacteria becoming antibiotic-resistant
The ability to drink milkas an adult is a helpfulmutation.
- have no effect- Example:
- CAC = valine
- CAT = valine
Types of Mutations1. gene mutations – only affects one gene
a. point mutation - a substitution of a single base pair - changes only one amino acid (if any!)
Types of Mutationsb. frameshift mutation
- a single base is added or deleted- changes every amino acid after mutation site
- also called a nonsense mutation
http://highered.mcgraw-hill.com/sites/0072552980/student_view0/chapter9/animation_quiz_5.html
Types of Mutations2.Chromosomal mutation – may affect
more than one geneExamples: nondisjunction, deletion, insertion, inversion, translocation
What can cause a mutation?***A mutation can be inherited, caused by
environmental agents, or happen spontaneously
Mutagen – anything environmental that can cause a change in DNA
Mutagens
Radiation – UV, X-rays, nuclear
Mutagens
Chemicals – asbestos, formaldehyde, chemicals in tobacco products
(many mutagens are also carcinogens – cancer causing)
Mutation Repair
Note: Our DNA mutates all the time, but our cells have repair mechanisms. It is the overexposure to a mutagen that causes the worst problems, because the cell cannot repair all of it in time. Also, repair effectiveness reduces with age.
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