Mutations

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Mutations

• Chapter 12.4

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Mutation

• ?A result of changes in individual genes or the
  gene arrangements on chromosomes
• Original code (order of bases) is changed
• 2 different kinds
• Gene mutation
• Chromosome mutation

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Gene Mutations

• ?Mutations occurring within a gene
• Usually a letter change, removal, or addition
• Three different types
• Deletion
• Insertion
• Point mutation

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Gene deletions and insertions

• Gene deletion ? nucleotide is left out
• Gene insertion ? an extra nucleotide is added
• These are called frame-shift mutations
• ?causes the order of bases to switch, which
  causes change in codons, which in turn changes
  amino acid sequence

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Point mutations

• Point mutation ? a base is substituted for one
  other base
• ?Will only affect one amino acid in the protein

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- Deletion
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Chromosome Mutations

• ?Mutations that occur within a chromosome or
  between chromosomes
• 4 different types
• Deletions
• Duplications
• Inversions
• Translocations

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Deletions and Duplications

• Chromosomal deletion ? part of a chromosome are
  removed
• Chromosomal duplication ? part of a chromosome is
  duplicated

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Inversion and Translocation

• Chromosomal inversion ? portion of a chromosome
  is reversed
• Chromosomal translocation ? part of one
  chromosome attaches to another, different
  chromosome

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Mutagens

• Mutagen ?an agent that causes a mutation
• environmental factors such as radiation, heat,
  and chemicals

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Passing On of Mutations

• ?Mutations that occur in body cells do not get
  passed on to offspring
• ?Mutations that occur in sex cells do get
  passed on to offspring

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Mutation and Evolution

• Mutations could cause a new allele for a
  characteristic
• ?Mutations could also be the fuel that drives
  evolution
• individuals that underwent mutations may be
  better suited for survival than the original