Thursday, May 14, 2009

8.7 Mutations Notes

Gene Mutations:
  • Mutations that affect a single gene
  • POINT MUTATION: one nucleotide is substituted for another DNA. May be fixed by DNA Polymerase
  • FRAMESHIFT MUTATION: insertion or deletion of a nucleotide in a DNA sequence, SHIFTS the entire sequence

Chromosomal Mutations:

  • Affects the entire chromosome (many genes)
  • GENE DUPLICATION: caused by exchange of unequal segments during crossing over. One chromosome has 2 copies of some genes and the other has no copies.
  • TRANSLOCATION: movement of piece of 1 chromosome to a non-homologous chromosome.

Potential Impact:

  • Chromosome mutations typically have a large effect on an organism
  • Point mutatiosn may result in premature STOP codons or amino acids with very different properties from the correct amino acid


  • Some mutations have no apparent effect.
  • A point mmutation may not change the amino acid coded for.
  • Even if a change occurs, it may be in the non-coding region that has no apparent effect.


  • Agents that can change DNA.

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