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Mutations

Mutations. Mutations. What causes them?. Any mistake or change in DNA sequence. Random or Environmental influences – X-rays, UV rays, radioactive materials, chemicals, cigarettes, medications. Chromosomal mutation : affects whole or part of a chromosome Gene mutation :

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Mutations

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  1. Mutations

  2. Mutations What causes them? Any mistake or change in DNA sequence Random or Environmental influences – X-rays, UV rays, radioactive materials, chemicals, cigarettes, medications

  3. Chromosomal mutation: affects whole or part of a chromosome Gene mutation: Changes to the bases in the DNA of ONE gene

  4. 1. Gene Mutations • Change in one or more nucleotides • Affects the amino acids and protein produced • 2 types

  5.  Point Mutation • Substitution: Change in a single base pair in DNA • Ex: The dog bit the CAT The dog bit the CAR

  6. Sickle Cell Anemia

  7. Some Point Mutations are Harmless • What amino acid is represented by the DNA sequence GGA? • What amino acid is represented by the DNA sequence GGC? • This change in the 3rd base of the codon is a point mutation, yet the amino acid would remain the same. Therefore, the protein would NOT be affected.

  8. Some Point Mutations are Harmless • This type of point mutation is called a silent mutation. • Silent Mutations are possible due to the redundancy in the genetic code.

  9.  Frameshift Mutation • Single base pair is added or deleted from DNA • Causes a shift in the “reading frame” • Ex: Cystic Fibrosis EX: cystic fibrosis

  10. Kinds of Frameshift Mutations • Insertion: one or more bases are added into the mRNA strand • Deletion: one or more bases are removed from the mRNA strand

  11. Nonsense Mutations • A point mutation or a shift in the reading frame can sometimes cause a premature STOP codon • This type of mutation is called a nonsense mutation • If the nonsense mutation occurs early in the mRNA sequence, the protein is greatly shortened and most likely non functional

  12. Some mutations are beneficial • Gain-of-function mutations produce a functional protein that results in an entirely new trait • These mutations are usually beneficial and result in an advantage in an organism’s environment • EX: The mutation that resulted in eyesight

  13. Practice – Name that Mutation 1 2 4 3 6 5

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