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Types of Mutations

Types of Mutations. Thanks to Ms. Sara Dozier and Ms. Kimball for many of these slides!. Mutations. Mistakes in the nucleotide sequence in the DNA of a cell Caused by: Errors during DNA replication UV light Radiation Toxic chemicals Some viruses Immune system. What is a Mutant?.

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Types of Mutations

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  1. Types of Mutations Thanks to Ms. Sara Dozier and Ms. Kimball for many of these slides!

  2. Mutations • Mistakes in the nucleotide sequence in the DNA of a cell • Caused by: • Errors during DNA replication • UV light • Radiation • Toxic chemicals • Some viruses • Immune system

  3. What is a Mutant?

  4. We are ALL Mutants!

  5. Why Mutate? • Mutations are a natural source of variation • Variety in a population is good! • Variation is essential to evolution • SOME mutations are good: help an organism survive and reproduce • SOME mutations are bad: cause disease or death • MOST mutations are neutral: do not help nor hurt • Often repaired or not expressed

  6. Do Mutations Matter? • Antibiotic resistance is due to mutations (GOOD for bacteria, BAD for us) • Tay Sachs Disease is due to a frame shift mutation (BAD for humans) • Some people are resistant to HIV infection due to a mutation in an immune cell receptor CCR5 (GOOD for those lucky ones!)

  7. HIV HIV is a virus - it’s not considered a living thing because it needs a host cell to reproduce and make proteins HIV affects the immune system, making it hard for an infected person to fight off other diseases HIV has a high mutation rate, which means it’s constantly changing and evolving This makes it very difficult to create a cure or vaccine

  8. Point Mutation • A single base in the DNA sequence is changed to another base • 3 types of point mutations: • Silent • Missense • Nonsense

  9. Silent Mutation • Type of point mutation • A nucleotide base changes, but the amino acid stays the same ORIGINAL DNA: TAC CGT ACG GAT AAG ACT MUTATED DNA: TAC CGT ACA GAT AAG ACT ORIGINAL RNA: AUG GCA UGC CUA UUC UGA MUTATED RNA: AUG GCA UGU CUA UUC UGA ORIGINAL AA: MET ALA CYS LEU PHE STOP MUTATED AA: MET ALA CYS LEU PHE STOP

  10. Missense Mutation • Type of point mutation • A nucleotide base changes which results in an amino acid to change ORIGINAL DNA: TAC CGT ACG GAT AAG ACT MUTATED DNA: TAC TGT ACA GAT AAG ACT ORIGINAL RNA: AUG GCA UGC CUA UUC UGA MUTATED RNA: AUG ACA UGC CUA UUC UGA ORIGINAL AA: MET ALA CYS LEU PHE STOP MUTATED AA: MET THR CYS LEU PHE STOP

  11. Nonsense Mutation • Type of point mutation • A nucleotide base changes which causes an early stop codon ORIGINAL DNA: TAC CGT ACG GAT AAG ACT MUTATED DNA: TAC CGT ACT GAT AAG ACT ORIGINAL RNA: AUG GCA UGC CUA UUC UGA MUTATED RNA: AUG GCA UGA CUA UUC UGA ORIGINAL AA: MET ALA CYS LEU PHE STOP MUTATED AA: MET ALA Stop

  12. Other types of Mutations • Reading Frames • Frameshift mutations • Insertion of an extra nucleotide OR • Deleting of a nucleotide

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