12-4 Mutations

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12-4 Mutations
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• Mutation change in genetic material
• Gene mutation changes in a single gene
• Chromosomal mutation changes in whole
  chromosomes

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Gene Mutations

• Point Mutations Changes in one or a few
  nucleotides
• Include substitutions, insertions, and deletions

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Types of Point Mutations

• Substitutions one base is changed to another
• Usually affects a single amino acid
• Insertions one base is inserted
• Deletions one base is deleted
• More dramatic changes
• Cause frameshift mutations
• Changes all amino acids after the
• point of change

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Chromosomal Mutations

• Changes in the number or structure of chromosomes
• May even change the number of copes of some genes

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4 Types of Chromosomal Mutations

• Deletions loss of all or part of a chromosome
• Duplications extra copies of parts of a
  chromosomes
• Inversions reverse direction of parts of a
  chromosomes
• Translocations part of one chromosome breaks
  off and attaches to another

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Chromosomal Mutations
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Significance of Mutations

• Most have little effect
• Dramatic changes usually harmful
• Producing defective proteins that dont do their
  job
• Mutations source of genetic variability!
• Can be very good! Useful!