Mutations final

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Mutations final

  1. 1. Mutations<br />
  2. 2.
  3. 3. Mutations<br />Occur when there is an error in DNA replication<br />Def: Change in genetic material<br />Mutagens<br />Physical or chemical agents that cause mutations<br />Ex: high energy radiation (x-ray or UV)<br />Ex. Chemicals (that are similar to DNA but cause incorrect base pairing)<br />
  4. 4. Mutation<br />Any change in the nucleotide sequence of DNA<br />Large or small<br />2 Main types<br />Base Substitutions (point mutations)<br />Insertions or deletions<br />
  5. 5. Base Substitution<br /><ul><li>Replacement of one base or nucleotide with another
  6. 6. Usually do not change amino acid
  7. 7. Sometimes causes a change in the protein made
  8. 8. Silent Mutation
  9. 9. When a substitution does not cause a change in the protein expressed by a gene
  10. 10. Remember some codons represent the same amino acid
  11. 11. Example: GAA and GAG both code for Glu</li></li></ul><li>Point MutationA point mutation is a simple change in one base of the gene sequence. This is equivalent to changing one letter in a sentence, such as this example, where we change the 'c' in cat to an 'h': <br />Original: The fat cat ate the wee rat.<br />Point Mutation: The fat hat ate the wee rat.<br />
  12. 12. Insertion or Deletion<br /><ul><li>Nucleotide is removed or added
  13. 13. More disastrous
  14. 14. mRNA is read as triplet codes
  15. 15. Adding/removing bases changes these three letter codes
  16. 16. Codons downstream from insertion/deletion will be regrouped and probably code for a non-working protein
  17. 17. Result: FRAMESHIFT MUTATION
  18. 18. Shift the “reading” frame of the genetic message</li></li></ul><li>Frameshift mutation<br />Original: The fat cat ate the wee rat.<br />Frame Shift: The fat caa tet hew eer at.<br />
  19. 19. Chromosomal Mutations<br /><ul><li>Involve changes in the number or structure of the chromosome
  20. 20. May change location of genes on chromosome
  21. 21. Include:
  22. 22. Deletions: loss of part of chromosome
  23. 23. Duplications: produce extra copies of parts of chromosome
  24. 24. Inversions: reverse direction of chromosome
  25. 25. Translocation: when one chromosome breaks off and attaches to another</li></li></ul><li>
  26. 26. Mutations<br />NOT always harmful<br />Some alter a protein in a beneficial way that may help species in a specific environment<br />If mutation is present in organisms gametes, it may be passed off to off-spring<br />Mutations are the ULTIMATE source for GENETIC DIVERSITY!!!<br />

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