Biology 205 DNA Mutation and Repair:

Chapter 19

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I.  Mutation

• Distinguish between the major types of Mutations
  • Point mutations
  • Chromosomal Mutations
  • Somatic vs germ-line mutations
• Explain the connection between mutation and adaptation: which comes first?
• Briefly discuss the importance of mutations in evolution

Note some evidence that the mutation rate of bacteria is not constant but may be affected by stress. See for instance:

J. L. Martinez, and F. Baquero Antimicrobial Agents and Chemotherapy, July 2000, p. 1771-1777, Vol. 44, No. 7 0066-4804

II. Describe the major classes of Point mutations

• Substitutions
  • Missense
    • Silent mutation
    • Neutral mutation
  • Nonsense
• Frameshift mutations
  • Insertions
  • Deletions
• Types of point mutations in terms of affect on phenotype
  • Forward, Back mutations
  • Discuss the mechanism of suppressor mutations
    • Intergenic See page 399
    • Intragenic

III. Discuss the main causes of mutations

Distinguish between spontaneous mutations and induced mutations

Discuss the mechanism of spontaneous mutations

• Substitution errors, Additions and deletions: Due to wobble. See p 401 fig 19.6
• Spontaneous Chemical Changes in nucleotides: examples
  • Depurination
  • Deamination fig 19.8

Discuss the causes of induced mutations

• Radiation
  • Ionizing Vs non ionizing
  • Formation of Thymine dimers by UV radiation fig 19.9

Discuss the main types of mutagens

• Base analogs example 5BU P 403 and figure 19.10
• Base modifying agents. fig 19.11
• Intercalating agents - See fig 19.12

IV. Discuss the main types of DNA repair mechanisms

• DNA polymerase proof reading. p 408 involves 3'---->5' exonuclease activity of DNA polymerase
• Photoreactivation
• Repair of alkylation damage by DNA repair enzymes.
• Dark repair systems. p 409