Mutations

1. Mutations Chapter 12.4

2. 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

3. Gene Mutations Mutations occurring within a gene • Usually a letter change, removal, or addition • Three different types: • Deletion • Insertion • Point mutation

4. 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

5. Point mutations • Point mutation  a base is substituted for one other base Will only affect one amino acid in the protein

6. Point Mutation - Deletion

7. Chromosome Mutations Mutations that occur within a chromosome or between chromosomes • 4 different types: • Deletions • Duplications • Inversions • Translocations

8. Deletions and Duplications • Chromosomal deletion  part of a chromosome are removed • Chromosomal duplication  part of a chromosome is duplicated

9. Inversion and Translocation • Chromosomal inversion  portion of a chromosome is reversed • Chromosomal translocation  part of one chromosome attaches to another, different chromosome

11. Mutagens • Mutagenan agent that causes a mutation • environmental factors such as radiation, heat, and chemicals

12. 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

13. 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