Mutations

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Mutations
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What is a mutation?

• Changes in the DNA sequence that affect genetic
  information
• NormalThesunwashotbuttheoldmandidnotgethishat.T
  he sun was hot but the old man did not get his
  hat.
• Translation changed in ribosomet hes unw ash
  otb utt heo ldm and idn otg ish at.
• Missing letter or basethe sun wsh otb utt heo
  ldm and idn otg ish at.

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Genetic mutations

• Not all are harmful
• Most cause little/no change
• Have to be reproductive cell mutations to repeat
  in future generations
• Somatic mutations not inheritable

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How do mutations happen?

• Environmental agents
• UV light, chemicals, radiation
• Meiosis
• more/less chromosomes
• Mistakes in DNA replication

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What happens when there is a mutation?

• The mistake can cause the cell to make an
  incorrect protein
• see a different phenotype than normal ex. White
  Buffalo
• If the mutation occurs in a single type of cell,
• it will affect only the cell that carries it
  ex. Skin cells
• If the mutation occurs in a sex cell,
• it can be passed to the offspring and affect
  their phenotype
• Mutations can introduce genetic variation
• the change can be helpful, harmful or neither

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Where do they happen?

• Gene Mutations
• replication
• transcription
• translation
• Chromosome Structural Changes
• Mitosis
• Meiosis

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Gene Mutations

• Point Mutations
• involve one nucleotide
• single point in a DNA sequence
• Substitute one base for another

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Gene Mutations

• Frameshift
• insertion or deletion of a base
• shifts entire sequence for translation
• different group of amino acids
• changes the protein function

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Chromosome Structural Changes

• Deletion- loss of all or part of chromosome
• - missing genes may prove fatal
• Duplication- segment repeated
• - usually harmless

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Chromosome Structural Changes

• Inversion- connection broken sequence
  reversed- may be fatal
• Translocation- non-homologous chromosomes
  sharing or exchanging information